1,3,5-Triazapenta-1,3-dienes: Useful building blocks for the synthesis of 1,2-dihydro-1,3,5-triazines and oligonitriles

FULL PAPER

DOI: 10.1002/ejoc.200600352

1,3,5-Triazapenta-1,3-dienes: Useful Building Blocks for the Synthesis of

1,2-Dihydro-1,3,5-triazines and Oligonitriles^[‡]

Nadine Heße,^[a]Roland Fröhlich,^[a]Birgit Wibbeling,^[a]and Ernst-Ulrich Würthwein*^[a]

Dedicated to Professor Jochen Mattay on the occasion of his 60th birthday

Keywords: 1,3,5-Triazapenta-1,3-dienes / Tautomerism / Triazines / Oligonitriles / DFT calculations

1,3,5-Triazapentadienes 1, prepared from amidines and imid-

oyl chlorides 2, have been used as nucleophilic building

blocks for the reactions with various electrophilic reagents.

With aldehydes 4 1,2-dihydrotriazines 3 were obtained,

whereas ketones 5 gave 3 or 1,3,5-triazahexa-1,3,5-trienes 6,

depending on the substitution pattern of 1. Acyl chlorides 7

reacted with 1 to give 1-oxa-3,5,7-triazahepta-1,3,5-trienes 8;

in a similar manner imidoyl chlorides 2 gave rise to the for-

mation of the new 1,3,5,7-tetraazahepta-1,3,5-trienes 9.

1-Oxa-3,5-diazinium salt 13 as cyclic electrophile produced,

when treated with 1g, 1-oxa-3,5,7,9,11-pentaazaundeca-

1,3,5,7,9-pentaene (14), a long oligonitrile with push-pull

substitution pattern. All new compounds were completely

characterized including X-ray diffraction for each type, indi-

cating rather twisted three-dimensional structures for the

open-chain compounds. The relative energies of 1,3,5-triaza-

pentadiene isomers were studied by DFT calculations [level:

B3LYP/6-31+G(d,p)], as well as the ring-chain tautomerism

Treatment of N-benzoylbenzimidoyl chloride 10 with 1 af- of selected examples.

forded the 1-oxa-3,5,7,9-tetraazanona-1,3,5,7-tetraenes 11,

or, depending on the substitution pattern, their ring-tauto-

meric compounds 12 with 1,2-dihydrotriazine structures.

Germany, 2006)

gen atoms. The open-chain compounds, namely oligoni-

triles, are interesting with regard to their electronic proper-

ties, which are characterized by competing π–π* and n–π*

interactions of the adjacent C=N moieties.^[3,4]This often

results in unusual three-dimensional structures with low ro-

tational barriers about the C–N single bonds. Besides the

synthesis, the full structural characterization of the new

open-chain compounds including X-ray diffraction analyses

constitutes a second focus of this work.

Introduction

1,3,5-Triazapenta-1,3-dienes are polyfunctional, nitro-

gen-rich analogs of pentadienes with two amidine subunits

forming an unsaturated N–C–N–C–N chain. On the other

hand, they may also be understood as formal products of

a nitrile dimerization, induced by an amine nucleophile. As

nitrogen analogs of β-diketones they possess great potential

as chelating ligands for various metal ions providing access

to six-membered metal complexes.^[1]They are accessible by

reaction of benzamidines with imidoyl halides as first de-

scribed by Ley und Müller.^[2]Depending on the number of

protons at the nitrogen atoms we differentiate primary

(three protons at the nitrogen atoms), secondary (two pro-

tons at the nitrogen atoms) and tertiary (one NH group)

triazapentadienes.

Results and Discussion

Seven secondary 1,3,5-triazapenta-1,3-dienes 1a–g (1b–

1g were unknown before) were prepared form benzamidine

and imidoyl halides 2a–g in 20–78% yield by applying a

modification^[1]of a procedure given by Ley and Müller^[2]

(Scheme 1).

In a similar manner, the tertiary 1,3,5-triazapenta-1,3-

diene 1h was prepared from the corresponding N-cyclopen-

tylpivalimidoyl chloride (2h) and N-phenylbenzamidine in

91% yield (Scheme 2).

In this report, we describe our experiments with 1,3,5-

triazapenta-1,3-dienes as nucleophiles in reactions with

various electrophiles in order to extend the length of the

unsaturated chain giving rise to a number of new heterocy-

clic and acyclic products with alternating carbon and nitro-

Two of the 1,3,5-triazapenta-1,3-dienes (1b,e) could be

characterized by X-ray diffraction (Figure 1 for 1b). In both

cases a twisted U-shape structure is adopted in the solid

state, which is subject of a weak intramolecular interaction

between one of the two amino protons N5H₂and nitrogen

[‡] Unsaturated Hetero Chains, XIV. Part XIII: Ref.^[3]

[a] Organisch-Chemisches Institut, Westfälische Wilhelms-

Universität,

Corrensstraße 40, 48149 Münster, Germany

Fax: +49-251-83-39772

E-mail: wurthwe@uni-muenster.de

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Scheme 1.

Figure 2. DFT-optimized structures for 1,3,5-triazapenta-1,3-diene

isomers with relative energies [kcal/mol], B3LYP/6-31+G(d,p) (incl.

ZPE).

Secondary 1,3,5-triazapenta-1,3-dienes (having a ter-

minal NH₂group or a tautomeric structure) are expected

to give condensation reactions with carbonyl compounds

like aldehydes and ketones, as it is known for simple amines

and amidines, leading to 1,2-dihydro-1,3,5-triazines or their

Scheme 2.

atom N1 (1b: 2.627 Å) and a strong interaction of the other open-chain tautomers 1,3,5-triazahexa-1,3,5-trienes. To the

amino protons with N3 of the neighboring molecule in the best of our knowledge, such reactions have not yet been

crystal lattice (1b: 2.013 Å). In this way, a continuous linear reported for 1,3,5-triazapenta-1,3-dienes.

polymeric structure is realized in the crystal, consisting of

Due to their amidine substructure, the 1,3,5-triazapenta-

···H–N(1A)H–CR=N(3)R···H–N(1A)H–CR=N(3)R···H 1,3-dienes do not react easily with benzaldehyde or pivalal-

motifs with H–N···H angles of 165.15°. Quantum chemical dehyde in the presence of base or activated molecular sieves.

model calculations [B3LYP/6-31+G(d)]^[5]predict for the However, catalysis and water removal by titanium tetrachlo-

(monomeric) parent compound the planar U form with the ride as first reported by White and Weingarten^[6]for the

intramolecular H bond as the structure with the lowest en- synthesis of aldimines and ketimines offers a successful

ergy (Figure 2). With calculated barriers of rotation of only method for condensation reaction using aldehydes and

2.7–7.4 kcal/mol the interconversion of the various struc- ketones as electrophiles.^[7,8]According to this method, three

tures is easily achieved under standard conditions.

different 1,2-dihydro-1,3,5-triazine derivatives 3a–c were

Figure 1. Molecular structure of 1b in the solid state (left: single molecule; right: two molecules with hydrogen bonding shown). Selected

structural parameters: bond lengths [Å]: N1–C2 1.288(2), C2–N3 1.411(2), N3–C4 1.294(2), C4–N5 1.350(2); bond angles [°]: N1–C2–

C3 124.32(13), C2–N3–C4 118.26(11), N3–C4–N5 125.30(13); torsional angles [°]: N1–C2–N3–C4–N5 72.04, C2–N3–C4–N5 6.99.

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Triazapentadienes as Building Blocks for Dihydrotriazines and Oligonitriles

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obtained using aldehydes 4 (Scheme 3), whereas the ketones

2-adamantanone (5a) und 9H-fluoren-9-one (5b) gave 3d–f

(Scheme 4). The structure of 3a in the solid state was deter-

mined by X-ray diffraction (Figure 3).

Figure 3. Molecular structure of 3a in the solid state. Selected

structural parameters: bond lengths [Å]: N1–C2 1.463(1), C2–N3

1.480(1), N3–C4 1.363(1), C4–N5 1.306(1); bond angles [°]: N1–

C2–C3 110.63(8), C2–N3–C4 115.58(8), N3–C4–N5 121.79(9), C4–

N5–C6 115.42(8), N5–C6–N1 126.65(9); torsional angles [°]: N1–

C2–N3–C4 42.75, C2–N3–C4–N5 –19.83, N3–C4–N5–C6 –11.42,

C4–N5–C6–N1 20.36, N5–C6–N1–C2 4.97.

Scheme 3.

Surprisingly, the 1,3,5-triazapenta-1,3-diene 1e, bearing a

cyclohexyl group at the nitrogen atom N1 instead of a 6b: –100.38°, –0.18°, 104.63°. Besides steric factors, elec-

phenyl group as in 1a,c,d behaves quite differently in con- tronic interactions between nitrogen lone-pairs and the ad-

densation reactions with 5a,b and benzophenone (5c) yield- jacent C=N π-systems, which are in competition to the

ing the 1,3,5-triazahexa-1,3,5-trienes 6a–c (Scheme 5), as polyene-type π–π* conjugation, are responsible for the ob-

determined by X-ray diffraction for 6a,b (Figure 4 for 6b). served conformations and configurations.

There is only very little known in the literature about 1,3,5-

The structural ambiguity of 3 and 6 is best explained

triazahexa-1,3,5-trienes;^[9]to the best of our knowledge 6a,b by ring-chain tautomerism, which is typical for unsaturated

are the first examples of this class of compounds studied hetero chains of the oligonitrile type (Scheme 6).^[10,11]Obvi-

by X-ray diffraction, which may be considered to consist ously, the equilibrium is very sensitive with respect to small

of nitrile trimers. Both structures exhibit rather nonplanar changes of the substitution pattern of the compounds in-

N=C–N=C–N=C substructures as it is seen from the dihe- volved,^[12]as can be seen by comparing 3d with 6a, which

dral angles along the chain: 6a: –94.25°, –7.60°, 121.36°; differ only in the substituent at N1 (phenyl vs. cyclohexyl).

Scheme 4.

Scheme 5.

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reaction is accompanied by a 1,5-proton shift resulting in a

continuous unsaturated C=N–C=N–C=O chain. Such com-

pounds (with tertiary amino function) have been synthe-

sized previously in our group by nucleophilic displacement

of 6-alkoxy-1-oxa-3,5-diazahexa-1,3,5-trienes using second-

ary amines as nucleophiles.^[13]The present method has the

advantage to allow the introduction of secondary amine

functionalities at C6, and is more versatile with regard to

the acylating agent (R³at C2).

The X-ray diffraction analysis of 8a (Figure 5) resulted

Figure 4. Molecular structure of 6b in the solid state. Selected in a rather irregular, twisted oligonitrile backbone with di-

structural parameters: bond lengths [Å]: N1–C2 1.265(2), C2–N3

hedral angles of –69.2°, –13.8°, 120.6°, 172.9°, 7.2° and

1.420(2), N3–C4 1.279(2), C4–N5 1.404(2), N5–C6 1.276(2); bond

–161.2° along the O1=C2–N3=C4–N5=C6–N7 chain,

angles [°]: N1–C2–C3 125.3(2), C2–N3–C4 119.1(1), N3–C4–N5

probably due to crystal packing forces, which may influence

the rather flexible N–C single bonds quite strongly.

120.8(1), C4–N5–C6 124.0(1); torsional angles [°]: N1–C2–N3–

C4 –100.4, C2–N3–C4–N5 –0.2, N3–C4–N5–C6 104.6.

Thus, aromatic substituents at N1 seem to favor the cyclic

tautomer, whereas the alkyl group shifts the equilibrium

towards the open-chain form. Quantum chemical calcula-

tions (B3LYP/6-31G*) for the gas phase indicate for both

systems (3d and 6a) a preferred open-chain structure, which

should be favored for cyclohexyl at N1 by 8 kcal/mol, but

for phenyl only by 2.5 kcal/mol. It should be mentioned

that the parent compound, 1,3,5-triazahexa-1,3,5-triene is

calculated to be higher in energy by 16–19 kcal/mol com-

pared to the corresponding cyclic tautomer. The calculated

barrier for ring opening amounts to 25–30 kcal/mol. Hence,

both electronic as well as packing forces may be the reason

for the observed structural preferences. In the case of 6c the

1

ring-chain tautomerism could be monitored by H NMR

spectroscopy. At low temperature ([D₈]THF, –233 K) a Figure 5. Molecular structure of 8a in the solid state. Selected

structural parameters: bond lengths [Å]: O1–C2 1.221(4), C2–N3

1.391(4), N3–C4 1.294(4), C4–N5 1.388(4), N5–C6 1.291(4), C6–

N7 1.363(4); bond angles [°]: O1–C2–C3 121.6(3), C2–N3–C4

121.1(3), N3–C4–N5 121.2(3), C4–N5–C6 123.4(3), N5–C6–N7

121.3(3); torsional angles [°]: O1–C2–N3–C4 –69.21, C2–N3–C4–

N5 –13.76, N3–C4–N5–C6 120.56, C4–N5–C6–N7 172.91.

60:40 ratio in favor for the chain structure was detected; at

higher temperature (328 K) an 80:20 ratio is present. More

polar solvents (e.g. [D₆]acetone) favor slightly the cyclic

structure (50:50 at 298 K).

The 1-oxa-3,5,7-triazahepta-1,4,6-triene 8d was prepared

from 1h and 4-toluoyl chloride (7a) in 46% yield after de-

protonation of the triazapentadiene using butyllithium

(Scheme 8). According to the mass spectra we found re-

gioselective attack at N5 producing the amide derivative 8d

without a mobile proton, which differs from 8a–c.

Scheme 6.

Treatment of 1,3,5-triazapenta-1,3-dienes 1a,f with the

In a similar manner as with the acyl halides 7, the triaza-

acid chlorides 7a,b lead – by regioselective acylation at pentadienes 1 also reacted with the imidoyl chlorides 2e,f,g

atom N5 – in 46–67% yield to the 1-oxa-3,5,7-triazahepta- at the terminal primary amino group to give the 1,3,5,7-

1,3,5-trienes 8a–c (Scheme 7). Interestingly, the acylation tetraazahepta-1,3,5-trienes 9a–c in 37–59% yield

Scheme 7.

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Scheme 8.

Scheme 9.

(Scheme 9). To the best of our knowledge, this class of com-

pounds has also never been described before. As a formal

nitrile trimer they present the next longer homologue in the

oligonitrile family after the “dimers” 1,3,5-triazapenta-1,3-

dienes 1. From the X-ray diffraction of 9a (Figure 6), a

three-dimensional structure was obtained, showing three

(Z)-configured C=N bonds and three C–N bonds with

gauche conformation resulting in a helix-type arrangement

of the oligonitrile main chain (torsional angles along the

N=C–N=C–N=C–N=C–NH₂chain: –1.23°, 77.56°, –7.15°

76.06°, 6.23° and 26.59°), as it is often found in oligonitrile

chemistry.^[4,10,11,13]We interpret these structural properties

by substantial electronic interactions of the lone pair of the

imino nitrogen atoms with the adjacent C=N double bonds

(n–π* interaction), which seem to be more important com-

pared to polyene-type π–π* conjugation, which would in-

duce a planar structure. The X-ray structure of 9b shows a

more irregular structure than 9a.

Figure 6. Molecular structure of 9a in the solid state. Selected

structural parameters: bond lengths [Å]: N1–C2 1.278(2), C2–N3

1.399(2), N3–C4 1.288(2), C4–N5 1.376(2), N5–C6 1.279(2), C6–

N7 1.357(2); bond angles [°]: N1–C2–C3 126.5(1), C2–N3–C4

121.7(1), N3–C4–N5 126.0(1), C4–N5–C6 129.9(1), N5–C6–N7

126.1(1); torsional angles [°]: N1–C2–N3–C4 77.56, C2–N3–C4–

N5 –7.15, N3–C4–N5–C6 76.06, C4–N5–C6–N7 6.23.

A further electrophile, which was treated successfully

with 1,3,5-triazapenta-1,3-dienes 1f,g, was N-benzoylbenz-

imidoyl chloride (10) (Scheme 10). It is easily available from where easy conformational changes about the C–N bonds

dibenzoylamine by chlorination using phosphorus penta- may be caused by the crystal packing forces during the

chloride.^[14]As in the previous cases, we found clean and crystallization.^[10]

regioselective electrophilic attack at the amino groups of

1f,g giving rise to 1-oxa-3,5,7,9-tetraazanona-1,3,5,7- ferently in reactions with 10 (Scheme 11). Here, all spectro-

tetraenes 11a,b in 35 and 42% yield. scopic and crystallographic evidence is in favor for 1,2-dihy-

However, 1,3,5-triazapenta-1,3-dienes 1a,d behave dif-

The X-ray diffraction structure of 11b (Figure 7) presents drotriazine structures 12a,b, which are formed in 44% and

a 3₁-helix (torsional angles along the chain: 40.73°, 8.93°, 18% yield, respectively (12b could not be purified com-

65.58°, 0.67°, 63.81°, 15.00°), whereas 11a shows a more pletely). Here again we observe the tendency of oligonitriles

irregular structure (torsional angles along the chain: to form cyclic tautomers, and again the terminal group at

–87.73°, 7.92°, –119.96°, 1.58°, 128.94°, –14.61°). Obvi- N1 in both 1,3,5-triazapenta-1,3-dienes is a phenyl ring

ously, small differences in the steric requirement of the pe- (vide supra), which seem once more to favor cyclic over

ripheral groups lead to different structures in the solid state, open-chain isomers. Among the three possibilities to form a

Scheme 10.

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contrast to other oligonitriles which incorporate five double

bonds, the present substitution pattern does not give rise to

a helix-type structure in the solid state. A more irregular

orientation of the chain is realized for 14 (torsional angles

starting from C=O: 53°, 4°, 56°, 0°, 108°, –8°, 122°, –160°).

Small changes in the substitution pattern again have great

influence on the crystal structure obtained.

Figure 7. Molecular structure of 11b in the solid state. Selected

structural parameters: bond lengths [Å]: O1–C2 1.236(4), C2–N3

1.377(4), N3–C4 1.294(4), C4–N5 1.372(4), N5–C6 1.291(4), C6–

N7 1.369(4), N7–C8 1.287(3), C8–N9 1.349; bond angles [°]: O1–

C2–C3 123.5(3), C2–N3–C4 124.9(3), N3–C4–N5 126.9(3), C4–

N5–C6 126.5(3), N5–C6–N7 125.8(3), C6–N7–C8 130.8(3), N7–

C8–N9 125.8(3); torsional angles [°]: O1–C2–N3–C4 40.73, C2–

N3–C4–N5 8.93, N3–C4–N5–C6 65.58, C4–N5–C6–N7 0.67, N5–

C6–N7–C8 63.81, C6–N7–C8–N9 15.00.

Figure 8. Molecular structure of 14 in the solid state. Bond param-

eters are not given because of low crystal quality.

cyclic six-membered system selectively, the one with a low-

energy extracyclic amide function is obtained as it is shown

by a X-ray structural analysis of 12a.

1-Oxa-3,5-diazinium salts 13 present powerful electro-

philes that provide access to N-acyloligonitriles by nucleo-

philic ring-opening reactions.^[4,15]The 1,3,5-triazapenta-1,3-

Conclusions

1,3,5-Triazapenta-1,3-dienes 1 are valuable nucleophilic

diene 1g reacts with 13 to yield the 1-oxa-3,5,7,9,11-penta- building blocks for the synthesis of various open-chain and

azaundeca-1,3,5,7,9-pentaene (14) in 17% yield (after heterocyclic compounds of the oligonitrile and 1,2-dihy-

recrystallization from triethylamine/ethyl acetate). With its drotriazine type. Simple carbonyl compounds like aldehydes

secondary terminal amino group, it is a new type of oligo- 4 and ketones 5 lead to 1,2-dihydrotriazines 3 or 1,3,5-tri-

nitrile derivative, not accessible before by other routes azahexa-1,3,5-trienes 6 in dependence of the substitution

(Scheme 12). There is mass-spectrometric evidence that pattern of 1. Effective chain elongation was achieved by the

other triazapentadienes also react with 13 by a similar con- use of the acyl chlorides 7 to give 1-oxa-3,5,7-triazahepta-

densation reaction; however, the isolation and purification 1,3,5-trienes 8 or imidoyl chlorides 2 to prepare the new

of these products failed. Unambiguous structural evidence 1,3,5,7-tetraazahepta-1,3,5-trienes 9. The azavinylogous

for the open-chain structure in the solid state was again electrophile N-benzoylbenzimidoyl chloride (10) made

obtained from X-ray analysis, although the analysis was of 1-oxa-3,5,7,9-tetraazanona-1,3,5,7-tetraenes 11 accessible,

poor quality due to the crystal properties (Figure 8). In or, depending on the substitution pattern, their ring-tauto-

Scheme 11.

Scheme 12.

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CDCl₃): δ = 24.4 (CH₂), 28.4 (CH₃), 33.4 (CH₂), 43.3 [C(CH₃)₃],

63.4 (CH), 150.1 (C=N) ppm. MS (70 eV): m/z (%) = 187 (1) [M⁺],

152 (23) [M⁺–Cl], 84 (100) [C₅H₁₀N⁺], 57 (38) [tBu⁺]. C₁₀H₁₈ClN

(187.76): calcd. C 63.99 H 9.67 N 7.46; found C 63.84 H 6.69 N

7.42.

meric compounds 12 with 1,2-dihydrotriazine structures.

1-Oxa-3,5-diazinium salt 13 is a valuable cyclic electrophile,

which gave 1-oxa-3,5,7,9,11-pentaazaundeca-1,3,5,7,9-pen-

taene 14, an extended oligonitrile with push-pull substitu-

tion pattern. All new compounds were completely charac-

terized including X-ray diffraction for each type. The highly

twisted three-dimensional structures are interpreted as re-

sults of competing n–π* and π–π* interactions, as indicated

by DFT calculations [level: B3LYP/6-31+G(d,p)]. The ring-

chain tautomerism was also studied theoretically, showing

the influence of N-terminal substituents on the ring-chain

equilibrium.

General Procedure for the Synthesis of 1,3,5-Triazapenta-1,3-dienes

1:^[2]The benzamidine (3.60 g, 30 mmol) was suspended in 20–

60 mL of diethyl ether. Then, an equimolar amount of the imidoyl

chloride 2 was added dropwise, and the reaction mixture was

stirred at room temperature for 2 h and at reflux temperature for

1 h. The precipitate formed was filtered off and treated with hot

water under ultrasonication in order to remove benzamidine hydro-

chloride. The remaining triazapentadiene hydrochloride was col-

lected and treated with 50 mL of 2  sodium hydroxide solution.

The resulting suspension was extracted with several portions of

dichloromethane until all solid was removed. The collected dichlo-

romethane extracts were dried with magnesium sulfate. Finally, the

solvent was removed in vacuo.

Experimental Section

Materials and Methods: IR: Nicolet 5DXC. ¹H NMR: Bruker WM

300 (300.13 MHz), Bruker AM 360 (360.13 MHz), Bruker AMX

400 (400.13 MHz) and Varian Unity plus (599.86 MHz), internal

reference tetramethylsilane. ¹³C NMR: Bruker WM 300

(75.47 MHz), Bruker AMX 400 (100.61 MHz) and Varian Unity

600 plus (150.85 MHz), internal reference tetramethylsilane or sol-

vent. MS: MAT C 312, Finnigan (70 eV). ESI-MS: Quattro LC-Z,

Micromass. MALDI (16–19 kV), nitrogen (337 nm, 3 ns); matrix:

DTBC {2-[(2E)-3-(4-tert-butylphenyl)-2-methylprop-2-enylidene]-

malononitrile}. UV/Vis: Cary 1 Bio, Varian. CHN: Elementar Va-

rio El III. Melting points are uncorrected. DC: SIL G/UV₂₅₄, Ma-

cherey–Nagel and silica gel F₂₅₄, Merck. Column chromatography:

Silica gel 60, Merck, or Alumina N, ICN Biomedicals, Activity

1. All solvents were rigorously dried by standard methods. When

necessary, the experiments were carried out with complete ex-

clusion of moisture (argon, septum-syringe technique) in glassware,

which was thoroughly dried by repeated heating under argon and

subsequent evacuation.

1,2-Bis[4-(methylphenyl)]-4-phenyl-1,3,5-triazapenta-1,3-diene (1b):

From benzamidine 10 (4.16 g, 34.6 mmol) in 20 mL of diethyl ether

and 2b (8.44 g, 34.6 mmol),^[20]dissolved in 40 mL of diethyl ether.

Yield: 3.38 g (10.3 mmol, 30%), yellow solid, m.p. 116–119 °C. IR

(KBr): ν = 3433 (m, NH ), 3292 (m, NH ), 3070 (s, CH_arom.), 3026

˜

2

(s, CH_arom.), 2916 (m, CH_aliph.), 2864 (m, CH_aliph.), 1643 (vs, C=N),

1610 (vs, C=C_arom.), 1587 (vs, C=C_arom.), 1568 (vs, C=C_arom.), 1564

(vs, C=C_arom.), 1501, (s), 1447 (s), 1394 (s), 1308 (s), 1283 (s), 1219

(s), 1177 (m), 1105 (m), 1034 (m), 1015 (m), 879 (m), 844 (m), 808

1

(m), 771 (s), 712 (m), 696 (m) cm^–1. H NMR (300 MHz, CDCl₃):

δ = 2.27 (s, 3 H, CH₃), 2.40 (s, 3 H, CH₃), 4.83 (br., 2 H, NH₂),

6.98 (m, 4 H, H_arom.), 7.23 (d, 2 H, CH_arom.), 7.43 (m, 3 H,

CH_arom.), 7.67 (m, 2 H, CH_arom.), 7.93 (d, 2 H, CH_arom.) ppm. ¹³C

NMR (75.47 MHz, CDCl₃): δ = 20.7 (CH₃), 21.3 (CH₃), 121.4,

126.9, 128.1, 128.6, 128.8, 129.2, 129.6, 131.1, 132.5 (C_arom.), 134.4

(i-C_arom.), 141.1 (i-C_arom.), 147.7 (i-C_arom.), 152.6 (C=N), 161.0

(C=N) ppm. MS (70 eV): m/z (%) = 327 (72) [M⁺], 326 (86) [M⁺–

1], 224 (67) [M⁺–PhCN], 223 (38) [M⁺–102], 208 (83)

[TolCNTol⁺], 118 (52) [TolCNH⁺], 107 (100) [TolNH₂⁺], 106 (57)

[TolNH⁺], 104 (37) [PhCNH⁺], 103 (75) [PhCN⁺], 91 (88) [Tol⁺],

65 (46) [C₅H₅⁺]. C₂₂H₂₁N₃(327.42): calcd. C 80.71 H 6.46 N 12.83;

found C 80.68 H 6.40 N 12.88.

4-Chloro-N-(4-methylphenyl)benzimidoyl Chloride (2c): In analogy

to a literature procedure^[16]from 4-chloro-N-(4-methylphenyl)-

benzamide^[17](12.28 g, 50 mmol) and phosphorus pentachloride

(10.41 g, 50 mmol) by heating to 110 °C for 1.5 h. Purification by

short-path distillation. Yellow solid. Yield: 12.87 g (49 mmol,

97%). B.p. 140 °C/0.042 mbar, m.p. 70 °C. ¹H NMR (300 MHz,

CDCl₃): δ = 2.36 (s, 3 H, CH₃), 6.92–6.95 (m, 2 H, CH_arom.), 7.18–

7.21 (m, 2 H, CH_arom.), 7.39–7.42 (m, 2 H, o-CH_arom.), 8.05–8.09

(m, 2 H, o-CH_arom.) ppm. ¹³C NMR (75.47 MHz, CDCl₃): δ =

21.0 (CH₃), 120.6 (C_arom.), 128.6 (C_arom.), 129.4 (o-C_arom.), 130.6

(o-C_arom.), 134.2 (i-C_arom.), 135.1 (i-C_arom.), 138.3 (i-C_arom.), 141.2

(i-C_arom.), 144.6 (C=N) ppm. MS (70 eV): m/z (%) = 230 (34)

[M(³⁷Cl)–Cl⁺], 228 (100) [M(³⁵Cl)–Cl⁺], 91 (44) [Tol⁺], 65 (29)

[C₅H₅⁺].

[21]

X-ray Crystal Structure Analysis of 1b:

Formula C₂₂H₂₁N₃, M

= 327.42, colorless crystal 0.30×0.25×0.20 mm, a = 10.229(3), b

= 9.738(3), c = 18.831(6) Å, β = 96.11(3)°, V = 1865.1(10) Å³, ρ_calcd.

= 1.166 gcm^–3, µ = 0.538 mm^–1, empirical absorption correction

(0.855 Յ T Յ 0.900), Z = 4, monoclinic, space group P2₁/c (No.

14), λ = 1.54178 Å, T = 223 K, ω/2θ scans, 3915 reflections col-

lected ( h, +k, +l), [(sinθ)/λ] = 0.62 Å^–1, 3794 independent (R_int

=

0.034) and 2824 observed reflections [I Ն 2σ(I)], 235 refined param-

eters, R = 0.041, wR₂= 0.124, max. residual electron density 0.22

(–0.15) e·Å^–3, hydrogen atoms at N1 from difference Fourier map,

other calculated and refined as riding atoms.

N-Cyclopentylpivalimidoyl Chloride (2h): In analogy to a literature

procedure^[18]from oxalyl chloride (7.62 g, 60 mmol), dissolved in

10 mL of dry chloroform, and N-cyclopentylpivalamide (10.15 g,

60 mmol),^[19]dissolved in 40 mL of dry chloroform at 0 °C. After

complete addition, the reaction mixture was stirred at 50 °C for

1 h. The solvent was removed in vacuo and the crude product was

purified by vacuum distillation using a Vigreux column. Colourless

liquid. Yield: 7.17 g (38 mmol, 64%), b.p. 60 °C/10 mbar. IR (KBr):

2-(4-Chlorophenyl)-1-(4-methylphenyl)-4-phenyl-1,3,5-triazapenta-

1,3-diene (1c): From benzamidine (3.54 g, 29.5 mmol), suspended

in 20 mL of diethyl ether, and 2c (7.80 g, 29.5 mmol), dissolved in

40 mL of diethyl ether. Yield: 4.14 g (11.9 mmol, 40%), yellow so-

lid, m.p. 131 °C. IR (KBr): ν = 3435 (m, NH ), 3294 (m, NH ),

˜

2

ν = 2962 (vs, CH_aliph.), 2870 (s, CH_aliph.), 1688 (vs, C=N), 1477 (s),

˜

3080 (s, CH_arom.), 3026 (m, CH_arom.), 2920 (m, CH_aliph.), 2866 (m,

1458 (s), 1392 (m), 1356 (m), 1342 (m), 1365 (s), 1342 (m), 1248 CH_aliph.), 2773 (m), 1645 (vs, C=N), 1612 (vs, C=C_arom.), 1585 (vs,

(m), 1205 (m), 1175 (m), 1066 (w), 1034 (m), 955 (s), 914 (s), 852

C=C_arom.), 1574 (vs, C=C_arom.), 1564 (vs, C=C_arom.), 1502 (vs,

C=C_arom.), 1485 (s), 1447 (s), 1398 (s), 1313 (s), 1302 (s), 1279 (s),

1221 (m), 1169 (m), 1105 (m), 1090 (s), 1032 (m), 1009 (s), 879 (m),

849 (s), 818 (m), 798 (s), 773 (m), 698 (s) cm^–1. ¹H NMR (300 MHz,

1

(m), 789 (s, C–Cl) cm^–1. H NMR (300 MHz, CDCl₃): δ = 1.23 (s,

9 H, CH₃), 1.48–1.63 (m, 4 H, CH₂), 1.73–1.90 (m, 4 H, CH₂), 4.08

(quint, ³J = 5.5 Hz, 1 H, CH) ppm. ¹³C NMR (75.47 MHz,

Eur. J. Org. Chem. 2006, 3923–3937

www.eurjoc.org

3929

N. Heße, R. Fröhlich, B. Wibbeling, E.-U. Würthwein

[D₆]DMSO): δ = 2.25 (s, 3 H, CH₃), 6.85 (br., 2 H, NH₂), 6.98 (m, ethyl ether, and the imidoyl chloride 2f (11.07 g, 60.0 mmol). Yield:

FULL PAPER

2 H, CH_arom.), 7.05 (m, 2 H, CH_arom.), 7.42–7.54 (m, 5 H, CH_arom.),

7.83 (m, 2 H, CH_arom.), 8.00 (m, 2 H, CH_arom.) ppm. ¹³C NMR

(75.47 MHz, CDCl₃): δ = 21.3 (CH₃), 122.1, 128.0, 128.9, 129.0,

10.53 g (38.8 mmol, 65%), colorless solid, m.p. 94–97 °C. IR (KBr):

ν = 3479 (s, NH ), 3445 (m, NH ), 3327 (br. s, NH ), 3182 (s,

˜

2

CH_arom.), 3065 (w, CH_arom.), 2959 (vs, CH_aliph.), 2907 (s, CH_aliph.),

129.5, 130.4, 131.3, 132.2, 135.2 (C_arom.), 135.6 (i-C_arom.), 136.0 (i- 2866 (s, CH_aliph.), 1649 (vs, C=N), 1578 (vs, C=C_arom.), 1475 (m),

C_arom.), 148.6 (i-C_arom.), 154.9 (C=N), 160.4 (C=N) ppm. MS

1450 (m), 1371 (s), 1273 (w), 1186 (s), 1078 (m), 1014 (m), 860 (m),

(70 eV): m/z (%) = 349 (35) [M(³⁷Cl)⁺], 347 (100) [M(³⁵Cl)⁺],

781 (s), 710 (m), 696 (s) cm^–1. ¹H NMR (300 MHz, CDCl₃): δ =

230(28) [C₁₄H₁₁(³⁷Cl)N⁺], 228 (89) [C₁₄H₁₁(³⁵Cl)N⁺], 194 (17), 138 1.21 (s, 9 H, CH₃), 1.43–1.48 (m, 4 H, CH₂), 1.52–1.75 (m, 4 H,

(16), 104 (78) [PhCNH⁺], 91 (74) [Tol⁺], 77 (29) [Ph⁺], 65 (36)

[C₅H₅⁺].C₂₁H₁₈ClN₃(349.60): calcd. C 72.51 H 5.22 N 12.08;

found C 72.42 H 5.14 N 11.95.

CH₂), 3.67 (m, 1 H, CH), 4.83 (br., 2 H, NH₂), 7.40–7.45 (m, 3 H,

CH_arom.), 7.79–7.82 (m, H, CH_arom.

2

)

ppm. ¹³C NMR

(75.47 MHz, CDCl₃): δ = 24.6, (CH₂), 28.5 (CH₃), 34.1 (CH₂), 39.2

[C(CH₃)₃], 58.6 (CH), 126.8 (C_arom.), 128.4 (o-C_arom.), 130.4

(C_arom.), 135.0 (i-C_arom.), 151.7 (C=N), 168.4 (C=N) ppm. MS

(70 eV): m/z (%) = 271 (28) [M⁺], 214 (50) [M⁺–tBu], 146 (100)

[214⁺–C₅H₈], 104 (59) [PhCNH⁺], 57 (28) [tBu⁺]. C₁₇H₂₅N₃

(271.38): calcd. C 75.23 H 9.28 N 15.48; found C 75.25 H 9.34 N

15.21.

2-tert-Butyl-1,4-diphenyl-1,3,5-triazapenta-1,3-diene (1d): From

benzamidine (3.72 g, 31.0 mmol), suspended in 60 mL of diethyl

ether, and 2d (6.06 g, 31.0 mmol)^[22]as a slowly crystallizing yellow

oil. Purity: ca. 95% (NMR). Yield: 1.67 g (6.0 mmol, 20%), m.p.

55–57 °C. IR (KBr): ν = 3454 (s, NH ), 3313 (s, NH ), 3176 (m,

˜

2

CH_arom.), 3060 (m, CH_arom.) 2964 (s, CH_aliph.), 2929 (m, CH_aliph.),

2866 (m, CH_aliph.), 1643 (vs, C=N), 1591(vs, C=C), 1583 (vs, C=C),

1560 (vs, C=C), 1477 (s), 1446 (s), 1386 (s), 1315 (m), 1242 (m),

1205 (m), 1174 (m), 1170 (m), 1072 (m), 1055 (m), 1016 (m), 877

2-tert-Butyl-1-isopropyl-4-phenyl-1,3,5-triazapenta-1,3-diene (1g):

From benzamidine (8.29 g, 69.0 mmol), suspended in 60 mL of di-

ethyl ether, and 2g (11.05 g, 69 mmol).^[24]Yield: 4.87 g (19.9 mmol,

1

(m), 779 (m), 750 (s), 696 (s) cm^–1. H NMR (300 MHz, CDCl₃):

29%), colorless solid, m.p. 107–109 °C. IR (KBr): ν = 3449 (s,

˜

δ = 1.33 (s, CH₃), 4.51 (br., 2 H, NH₂), 6.85–6.94 (m, 3 H, CH_arom.),

7.13–7.18 (m, 2 H, CH_arom.), 7.27–7.40 (m, 3 H, CH_arom.), 7.47–

7.50 (m, 2 H, CH_arom.) ppm. ¹³C NMR (75.47 MHz, CDCl₃): δ =

28.3 (CH₃), 39.7 [C(CH₃)₃], 120.9, 122.4, 126.6, 128.4 (C_arom.),

130.5 (i-C_arom.), 130.5 (C_arom.), 134.6 (i-C_arom.), 150.3 (C=N), 173.6

(C=N) ppm. MS (70 eV): m/z (%) = 279 (28) [M⁺], 278 (12) [M⁺–

1], 222 (100) [M⁺–tBu], 119 (24) [C₇H₇N₂⁺], 104 (55) [PhCNH⁺],

77 (23) [Ph⁺], 57 (17) [tBu⁺]. C₁₈H₂₁N₃(279.32). HR MS: calcd.

280.1814; found 280.1849 [C₁₈H₂₁N₃+H⁺].

NH₂), 3302 (s, NH₂), 3269 (s, NH₂), 3150 (s), 3032 (s, CH_arom.),

2961 (vs, CH_aliph.), 2926 (s, CH_aliph.), 2868 (s, CH_aliph.), 1645 (vs,

C=N), 1591 (vs, C=C_arom.), 1574 (vs, C=C_arom.), 1499 (m,

C=C_arom.), 1477 (m), 1454 (s), 1379 (vs), 1362 (s), 1271 (m), 1184

(s), 1134 (m), 1047 (m), 1026 (m), 945 (m), 868 (m), 785 (m), 698

(s) cm^–1. H NMR (300 MHz, CDCl₃): δ = 1.07 [d, J = 6.2 Hz, 6

H, CH(CH₃)₂], 1.22 [s, 9 H, C(CH₃)₃], 3.46 (sept, ³J = 6.2 Hz, 1

H, CH), 4.66 (br., 2 H, NH₂), 7.37–7.46 (m, 3 H, CH_arom.), 7.78–

7.82 (m, 2 H, CH_arom.) ppm. ¹³C NMR (75.47 MHz, CDCl₃): δ =

23.6 [CH(CH₃)₂], 28.6 [C(CH₃)₃], 39.1 [C(CH₃)₃], 48.1 (CH), 126.8

(C_arom.), 128.4 (o-C_arom.), 130.5 (C_arom.), 135.0 (i-C_arom.), 151.7

(C=N), 168.1 (C=N) ppm. MS (70 eV): m/z (%) = 245 (20) [M⁺],

188 (66) [M⁺–tBu], 146 (100) [C₈H₈N₃⁺], 104 (54) [PhCNH⁺], 84

(27), 77 (13) [Ph⁺], 57 (27) [tBu⁺]. C₁₅H₂₃N₃(245.35): calcd. C

73.43 H 9.45 N 17.13; found C 73.37 H 9.26 N 17.14.

1

3

2-tert-Butyl-1-cyclohexyl-4-phenyl-1,3,5-triazapenta-1,3-diene (1e):

From benzamidine (6.64 g, 55.0 mmol), suspended in 60 mL of di-

ethyl ether, and 2e (11.10 g, 55.0 mmol).^[23]Yield: 12.17 g

(42.7 mmol, 78%), colorless solid, m.p 101–104 °C. IR (KBr): ν =

˜

3462 (s, NH₂), 3452 (m, NH₂), 3308 (br. s, NH₂), 3161 (s, CH_arom.),

2962 (s, CH_aliph.), 2924 (s, CH_aliph.), 2853 (s, CH_aliph.), 1651 (vs,

C=N), 1591 (vs, C=C_arom.), 1576 (vs, C=C_arom.), 1499 (w), 1477

(w), 1448 (s), 1377 (vs), 1365 (s), 1275 (m), 1184 (s), 1078 (m), 1042

(m), 1016 (m), 960 (m), 889 (m), 866 (m), 785 (m), 696 (s) cm^–1.

¹H NMR (300 MHz, CDCl₃): δ = 1.22 (s, 9 H, CH₃), 1.15–1.43 (m,

6 H, CH₂), 1.54–1.71 (m, 4 H, CH₂), 3.08–3.15 (m, 1 H, CH), 4.79

(br., 2 H, NH₂), 7.37 (m, 3 H, CH_arom.), 7.78–7.81 (m, 2 H,

CH_arom.) ppm. ¹³C NMR (75.47 MHz, CDCl₃): δ = 25.0 (CH₂),

25.8 (CH₂), 28.6 (CH₃), 33.6 (CH₂), 39.1 [C(CH₃)₃], 56.5 (CH),

126.9, 128.4, 130.4 (C_arom.), 135.2 (i-C_arom.), 152.6 (C=N), 167.8

(C=N) ppm. MS (70 eV): m/z (%) = 285 (20) [M⁺], 228 (41) [M⁺–

tBu], 146 (100) [228⁺–C₆H₁₀], 104 (58) [PhCNH⁺], 84 (24)

[C₆H₁₂⁺], 57 (24) [C₄H₉⁺]. C₁₈H₂₇N₃(285.41): calcd. C 75.74 H

9.53 N 14.72; found C 75.56 H 9.16 N 14.76.

2-tert-Butyl-1-cyclopentyl-4,5-diphenyl-1,3,5-triazapenta-1,3-diene

(1h): From N-phenylbenzamidine (3.94 g, 20.0 mmol),^[7]suspended

in 60 mL of diethyl ether, and 2f (3.57 g, 20.0 mmol). Yield: 6.30 g

(18.1 mmol, 91%), light yellow solid, m.p 84–85 °C. IR (KBr): ν =

˜

3391 (m, NH), 3061 (m, CH_arom.), 3026 (m, CH_arom.), 2957 (s,

CH_aliph.), 2908 (m, CH_aliph.), 2868 (m, CH_aliph.), 1655 (vs, C=N),

1587 (s, C=C_arom.), 1553 (vs, C=C_arom.), 1502 (vs, C=C_arom.), 1483

(s), 1464 (m), 1447 (m), 1400 (m), 1340 (s), 1256 (s), 1219 (m), 1200

1

(m), 916 (m), 787 (m), 766 (m), 698 (s) cm^–1. H NMR (300 MHz,

CDCl₃): δ = 1.02–1.08 (m, 12 H, CH₂/CH₃), 1.49 (br., 5 H, CH₂),

4.02 (br., 1 H, CH), 4.35 (br., 1 H, NH), 6.90–7.01 (m, 1 H,

CH_arom.), 7.03 (m, 2 H, CH_arom.), 7.20–7.25 (m, 2 H, CH_arom.),

7.37–7.39 (m, 3 H, CH_arom.), 8.00–8.01 (m, 2 H, CH_arom.) ppm.¹³C

NMR (75.47 MHz, CDCl₃): δ = 23.7 (CH₂), 28.4 (CH₃), 34.2

(CH₂), 38.3 [C(CH₃)₃], 52.8 (CH), 122.0, 122.2, 127.9, 127.9, 128.1

(C_arom.), 129.8 (C_arom.), 137.7 (i-C_arom.), 151.1 (i-C_arom.), 158.4

(C=N), 160.2 (C=N) ppm. MS (70 eV): m/z (%) = 347 (15) [M⁺],

290 (10) [M⁺–tBu], 255 (66) [M⁺–PhNH], 222 (22) [C₁₄H₁₂N₃⁺],

180 (100) [PhCNPh⁺], 127 (15), 84 (15) [C₅H₁₀N⁺], 77 (47) [Ph⁺],

57 (20) [tBu⁺]. C₂₃H₂₉N₃(347.48): calcd. C 79.50 H 8.41 N 12.09;

found C 79.44 H 8.34 N 12.07.

[21]

X-ray Crystal Structure Analysis of 1e:

Formula C₁₈H₂₇N₃, M

= 285.43, colorless crystal 0.30×0.25×0.20 mm, a = 10.678(1), b

=

11.675(1), 28.606(1) Å,

c

=

V

=

3566.2(5) Å³, ρ_calcd.

=

1.063 gcm^–3, µ = 0.065 mm^–1, empirical absorption correction

(0.981 Յ T Յ 0.987), Z = 8, orthorhombic, space group Pbca (No.

61), λ = 0.71073 Å, T = 198 K, ω and φ scans, 7651 reflections

collected ( h, k, l), [(sinθ)/λ] = 0.66 Å^–1, 4200 independent (R_int

= 0.029) and 3061 observed reflections [I Ն 2σ(I)], 193 refined pa-

rameters, R = 0.049, wR₂= 0.130, max. residual electron density

0.21 (–0.18) e·Å^–3, hydrogen atoms at N1 from difference Fourier

map, other calculated and refined as riding atoms.

General Procedure for the Reaction of 1,3,5-Triazapentadienes with

Carbonyl Compounds:^[7,25]Under argon, triazapentadiene 1

(2.50 mmol), the carbonyl compound (2.5 mmol) and triethylamine

2-tert-Butyl-1-cyclopentyl-4-phenyl-1,3,5-triazapenta-1,3-diene (1f): (5 mmol) were dissolved in 15 mL of dry toluene. At 0 °C, a solu-

From benzamidine (7.25 g, 60.0 mmol), suspended in 60 mL of di- tion of titanium tetrachloride (1.25 mmol), dissolved in 5 mL dry

3930

www.eurjoc.org

Eur. J. Org. Chem. 2006, 3923–3937

Triazapentadienes as Building Blocks for Dihydrotriazines and Oligonitriles

FULL PAPER

toluene, was added slowly. After stirring at room temperature for

1 d, the orange reaction mixture was filtered using a glass frit,

which was half filled with Celite. Vacuum was applied after com-

plete precipitation of the suspension. The clear, colorless filtrate

was freed from the solvent in vacuo. The crude product was puri-

fied by column chromatography.

3.60 mmol). Column chromatography (pentane/TBME, 10:1 + 2%

triethylamine as eluent). Yield 0.28 g (0.82 mmol, 23%), colorless

solid. R_f(DC) = 0.24 (silica gel, pentane/TBME, 10:1 + 2% triethyl-

amine), m.p. 102–104 °C. IR (KBr): ν = 3057 (m, CH_arom.), 3026

˜

(m, CH_arom.), 2999 (m, CH_arom.), 2970 (s, CH_aliph.), 2955 (s,

CH_aliph.), 2872 (s, CH_aliph.), 1612 (s, C=N), 1576 (s, C=C_arom.), 1522

(vs, C=C_arom.), 1487 (m), 1458 (m), 1448 (s), 1408 (s), 1389 (m),

1367 (s), 1358 (s), 1321 (s), 1317 (s), 1298 (s), 1283 (m), 1217 (m),

1194 (m), 1159 (s), 1136 (s), 1115 (m), 1063 (m), 1024 (m), 957 (m),

1,2,4,6-Tetraphenyl-1,2-dihydro-1,3,5-triazine (3a): From triphenyl-

triazapentadiene 1a (0.60 g, 2.00 mmol)^[1,2]and benzaldehyde

(0.21 g, 2.00 mmol). Column chromatography (pentane/TBME,

10:1 + 2% triethylamine). Yield 0.20 g (0.52 mmol, 26%), yellow

solid. R_f(DC) = 0.13 (silica gel, pentane/TBME, 10:1 + 2% triethyl-

910 (m), 868 (m), 802 (m), 764 (m), 696 (s) cm^–1¹H NMR

.

(300 MHz, CDCl₃): δ = 0.94 (s, 9 H, CH₃), 1.42–1.57 (m, 12 H,

CH₃/CH₂), 1.57–1.67 (m, 2 H, CH₂), 1.69–1.75 (m, 2 H, CH₂),

1.88–1.94 (m, 1 H, CH₂), 4.14 (quint, 1 H, CH), 4.60 (s, 1 H,

amine), m.p. 154–155 °C. IR (KBr): ν = 3088 (m, CH_arom.), 3058

˜

(s, CH_arom.), 3026 (s, CH_arom.), 2924 (s, CH_arom.), 1605 (vs, C=N),

1597 (s, C=C_arom.), 1589 (vs, C=C_arom.), 1579 (s, C=C_arom.), 1514

(vs, C=C_arom.), 1489 (vs), 1458 (s), 1445 (s), 1410 (vs), 1337 (vs),

1327 (vs), 1282 (s), 1256 (vs), 1182 (s), 1151 (s), 1107 (s), 1069 (s),

1020 (s), 928 (s), 899 (s), 851 (s), 798 (s), 779 (s), 756 (s), 744 (vs),

CH_quart.), 7.34–7.39 (m, 3 H, CH_arom.), 8.14–8.17 (m, 2 H, CH_arom.

)

ppm. ¹³C NMR (75.47 MHz, CDCl₃): δ = 22.8 (CH₂), 23.3 (CH₂),

26.1 (CH₃), 30.0 (CH₃), 30.1 (CH₂), 32.3 (CH₂), 38.7 [C(CH₃)₃],

39.0 [C(CH₃)₃], 61.7 (CH), 75.1 (C_quart.), 127.8, 127.9, 129.7

(C_arom.), 137.2 (i-C_arom.), 160.0 (C=N), 175.5 (C=N) ppm. MS

(70 eV): m/z (%) = 282 (100) [M⁺–tBu], 214 (75) [282⁺–C₅H₈], 104

(42) [PhCNH⁺], 69 (27) [C₅H₉⁺]. C₂₂H₃₃N₃(339.49): calcd. C 77.83

H 9.80 N 12.38; found C 77.78 H 9.69 N 12.33.

1

710 (vs), 692 (vs) cm^–1. H NMR (300 MHz, CDCl₃): δ = 6.41 (s,

1 H, CH), 6.97–7.00 (m, 2 H, CH_arom.), 7.06–7.08 (m, 3 H,

CH_arom.), 7.18–7.44 (m, 9 H, CH_arom.), 7.69–7.72 (m, 2 H,

CH_arom.), 7.76–7.78 (m, 2 H, CH_arom.), 8.36–8.40 (m, 2 H, CH_arom.

)

ppm. ¹³C NMR (75.47 MHz, CDCl₃): δ = 78.7 (C_quart.), 124.9,

125.9, 126.1, 128.1, 128.3, 128.4, 128.86, 128.92, 130.1, 130.4, 131.2

(C_arom.), 134.8 (i-C_arom.), 136.5 (i-C_arom.), 141.7 (i-C_arom.), 144.2 (i-

C_arom.), 158.4 (C=N), 160.7 (C=N) ppm. MS (70 eV): m/z (%) =

387 (84) [M⁺], 310 (42) [M⁺–Ph], 283 [M⁺–PhCNH], 180 (100)

[PhCNPh⁺], 104 (26) [PhCNH⁺], 77 (54) [Ph⁺]. C₂₇H₂₁N₃(387.47):

calcd. C 83.69 H 5.46 N 10.84; found C 83.26 H 5.37 N 10.76.

1Ј,4Ј,6Ј-Triphenyl-1Ј,2Ј-dihydrospiro[adamantane-2,2Ј-[1,3,5]tri-

azine] (3d): From 1a (1.00 g, 3.00 mmol)^[1,2]and 2-adamantanone

(0.45 g, 3.00 mmol). Column chromatography (pentane/TBME,

20:1). Yield 0.32 g (0.70 mmol, 25 %), colorless solid, R_f(DC) =

0.24 (silica gel, pentane/TBME, 20:1), m.p 190 °C. IR (KBr): ν =

˜

3082 (m, CH_arom.), 3055 (m, CH_arom.), 3024 (m, CH_arom.), 2951 (s,

CH_aliph.), 2935 (s, CH_aliph.), 2920 (vs, CH_aliph.), 2912 (vs, CH_aliph.),

2854 (s, CH_aliph.), 1605 (s, C=N), 1570 (s, C=C_arom.), 1514 (vs,

C=C_arom.), 1485 (vs, C=C_arom.), 1445 (s), 1379 (m), 1331 (vs), 1325

(s), 1312 (s), 1296 (s), 1259 (m), 1246 (s), 1213 (m), 1171 (m), 1119

(s), 1059 (m), 1026 (m), 999 (m), 951 (m), 768 (m), 756 (m), 719

X-ray Crystal Structure Analysis of 3a:^[21]Formula C₂₇H₂₁N₃, M =

387.47, colorless crystal 0.60×0.60×0.50 mm, a = 13.237(2), b =

10.746(1), c = 14.905(2) Å, β = 110.63(1)°, V = 1984.2(4) Å³, ρ_calcd.

= 1.297 gcm^–3, µ = 0.597 mm^–1, empirical absorption correction

(0.716 Յ T Յ 0.755), Z = 4, monoclinic, space group P2₁/n (No.

14), λ = 1.54178 Å, T = 223 K, ω/2θ scans, 8088 reflections col-

1

(s), 702 (s) cm^–1. H NMR (300 MHz, CDCl₃): δ = 1.61 (d, 4 H,

CH/CH₂), 1.76 (s, 2 H, CH/CH₂), 1.94 (br., 2 H, CH/CH₂), 2.11

(s, 2 H, CH/CH₂), 2.33 (d, 2 H, CH/CH₂), 2.66 (d, 2 H, CH/CH₂),

7.03–7.09 (m, 3 H, CH_arom.), 7.19–7.22 (m, 2 H, CH_arom.), 7.27–

7.34 (m, 3 H, CH_arom.), 7.44–7.46 (m, 3 H, CH_arom.), 7.82–7.85 (m,

2 H, o-CH_arom.), 8.41–8.44 (m, 2 H, o-CH_arom.) ppm. ¹³C NMR

(75.47 MHz, CDCl₃): δ = 27.1 (CH), 27.2 (CH), 33.7 (CH₂), 33.9

(CH₂), 34.0 (CH₂), 38.0 (CH₂), 77.9 (C_quart.), 127.6, 127.9, 128.0,

128.1, 130.2, 130.5, 131.0, 132.3 (C_arom.), 136.2 (i-C_arom.), 137.0 (i-

lected ( h, –k, l), [(sinθ)/λ] = 0.62 Å^–1, 4048 independent (R_int

=

0.042) and 3819 observed reflections [I Ն 2σ(I)], 272 refined param-

eters, R = 0.034, wR₂= 0.091, max. residual electron density 0.22

(–0.16) e·Å^–3, hydrogen atoms calculated and refined as riding

atoms.

2-tert-Butyl-1,4,6-triphenyl-1,2-dihydro-1,3,5-triazine (3b): From

triphenyltriazapentadiene 1a (1.00 g, 3.00 mmol)^[1,2]and pivalal-

dehyde (0.26 g, 3.00 mmol). Column chromatography (pentane/

TBME, 10:1 + 2 % triethylamine as eluent). Yield 0.39 g

(1.06 mmol, 35%), yellow solid. R_f(DC) = 0.33 (silca gel, pentane/

C

_arom.), 139.9 (i-C_arom.), 158.6 (C=N), 166.1 (C=N) ppm. MS

(70 eV): m/z (%) = 431 (100) [M⁺], 354 (23) [M⁺–Ph], 180 (95)

[PhCNPh⁺], 104 (14) [PhCNH⁺], 77 (29) [Ph⁺]. C₃₀H₂₉N₃(431.55):

calcd. C 83.49 H 6.77 N 9.74; found C 83.35 H 6.84 N 9.56.

TBME, 10:1 + 2% triethylamine), m.p. 142–143 °C. IR (KBr): ν =

˜

6Ј-tert-Butyl-1Ј,4Ј-diphenyl-1Ј,2Ј-dihydrospiro[adamantane-2,2Ј-

[1,3,5]triazine] (3e): From 1d (0.84 g, 3.00 mmol) and 2-ada-

mantanone (0.45 g, 3.00 mmol). Column chromatography (pen-

tane/TBME, 20:1). Yield 0.36 g (0.90 mmol, 29%), colorless solid.

R_f(DC) = 0.38 (silica gel, pentane/TBME, 20:1), m.p. 155 °C. IR

3066 (m, CH_arom.), 3028 (m, CH_arom.), 2961 (s, CH_aliph.), 2926 (m,

CH_aliph.), 2868 (m, CH_aliph.), 1610 (s, C=N), 1570 (s, C=C_arom.),

1533 (vs, C=C_arom.), 1483 (s), 1477 (s), 1447 (s), 1398 (s), 1393 (s),

1325 (s), 1290 (s), 1256 (s), 1171 (m), 1105 (s), 1067 (m), 1042 (m),

1034 (s), 1018 (s), 1001 (m), 924 (m), 901 (m), 881 (m), 812 (s),

781(s), 760 (s), 733 (m), 712 (vs), 692 (s) cm^–1. ¹H NMR (300 MHz,

CDCl₃): δ = 1.20 (s, 9 H, CH₃), 5.10 (s, 1 H, CH), 6.98–7.46 (m,

11 H, CH_arom.), 7.90–7.92 (m, 2 H, CH_arom.), 8.38 (m, 2 H,

CH_arom.) ppm. ¹³C NMR (75.47 MHz, CDCl₃): δ = 26.4, (CH₃),

40.0 [C(CH₃)₃], 85.5 (C_quart.), 125.0, 128.0, 128.1, 128.4, 128.9,

129.8, 130.3, 131.3 (C_arom.), 135.5 (i-C_arom.), 136.5 (i-C_arom.), 146.4

(i-C_arom.), 158.0 (C=N), 163.1 (C=N) ppm. MS (70 eV): m/z (%) =

310 (79) [M⁺–tBu], 180 (11) [PhCNPh⁺], 104 (100) [PhCNH⁺], 77

(53) [Ph⁺]. C₂₅H₂₅N₃(367.47): calcd. C 81.71 H 6.86 N 11.43;

found C 81.71 H 6.78 N 11.40.

(KBr): ν = 3080 (m, CH_arom.), 3065 (m, CH_arom.), 3026 (m,

˜

CH_arom.), 2980 (s, CH_aliph.), 2959 (m, CH_aliph.), 2934 (s, CH_aliph.),

2924 (vs, CH_aliph.), 2903 (vs, CH_aliph.), 2853 (s, CH_aliph), 1609 (vs,

C=N), 1574 (s, C=C_arom.), 1529 (vs, C=C_arom.), 1487 (s), 1447 (s),

1362 (s), 1325 (s), 1296 (s), 1290 (s), 1273 (m), 1244 (m), 1173 (s),

1161 (m), 1121 (m), 1072 (m), 1026 (m), 783 (m), 759 (m), 729 (m),

1

704 (vs), 698 (vs) cm^–1. H NMR (300 MHz, CDCl₃): δ = 1.13 (s,

9 H, CH₃), 1.54 (br., 6 H, CH₂), 1.72 (br., 4 H, CH₂), 1.90 (br., 2

H, CH), 2.34 (br., 2 H, CH), 6.78 (br., 1 H, CH_arom.), 7.15–7.25

(m, 3 H, CH_arom.), 7.41–7.43 (m, 4 H, CH_arom.), 8.28–8.32 (m, 2

H, o-CH_arom.) ppm. ¹³C NMR (75.47 MHz, CDCl₃): δ = 27.1

(CH₂), 27.2 (CH), 29.8 (CH₃), 34.1 (CH₂), 38.0 (CH₂), 40.0

2,6-Di-tert-butyl-1-cyclopentyl-4-phenyl-1,2-dihydro-1,3,5-triazine

(3c): From 1f (0.98 g, 3.60 mmol) and pivalaldehyde (0.31 g, [C(CH₃)₃], 78.0 (C_quart.), 128.0, 130.0, 132.3 (C_arom.), 137.2

Eur. J. Org. Chem. 2006, 3923–3937

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3931

N. Heße, R. Fröhlich, B. Wibbeling, E.-U. Würthwein

FULL PAPER

(i-C_arom.), 140.0 (i-C_arom.), 158.4 (C=N), 176.1 (C=N) ppm. MS

λ = 1.54178 Å, T = 223 K, ω/2θ scans, 5519 reflections collected

(70 eV): m/z (%) = 411 (67) [M⁺], 354 (100) [M⁺–tBu], 334 (14) (+h, –k, l), [(sinθ)/λ] = 0.62 Å^–1, 5244 independent (R_int= 0.028)

[M⁺– Ph], 263 (90) [M⁺– AdN], 251 (25) [M⁺– 160], 160 (16)

and 3360 observed reflections [I Ն 2σ(I)], 565 refined parameters,

[tBuCNPh⁺], 104 (41) [PhCNH⁺], 57 (14) [tBu⁺]. C₂₈H₃₃N₃R = 0.063, wR₂= 0.194, max. residual electron density 0.34 (–0.25)

(411.56): calcd. C 81.71 H 8.08 N 10.21; found C 81.71 H 7.95 N

10.16.

e·Å^–3, hydrogen atoms calculated and refined as riding atoms.

2-tert-Butyl-1-cyclohexyl-4-phenyl-6-(9H-fluorene-9-ylidene)-1,3,5-

triazahexa-1,3,5-triene (6b) and 6Ј-tert-Butyl-1Ј-cyclohexyl-4Ј-

phenyl-1Ј,2Ј-dihydrospiro[9H-fluorene-9,2Ј-[1,3,5]triazine] (6bЈ):

From 1e (0.86 g, 3.00 mmol) and 9H-fluoren-9-one (0.54 g,

3.00 mmol). Column chromatography (acetone). In solution, the

compound exists in equilibrium with its cyclic tautomer (dihydro-

triazine) (Scheme 13). Yield 0.31 g (0.70 mmol, 23%), yellow solid.

6Ј-tert-Butyl-1Ј,4Ј-diphenyl-1Ј,2Ј-dihydrospiro[9H-fluorene-9,2Ј-

[1,3,5]triazine] (3f): From 1d (0.84 g, 3.00 mmol), 9H-fluoren-9-one

(0.54 g, 3.00 mmol), triethylamine (0.61 g, 6.00 mmol) and TiCl₄

(0.29 g, 1.50 mmol). Column chromatography (pentane/TBME,

20:1). High purity according to the NMR spectra, but small de-

ficiencies in the C, H, N analyses. Yield 0.08 g (0.20 mmol, 6%),

yellow solid. R_f(DC) = 0.13 (silica gel, pentane/TBME, 20:1), m.p.

R (DC) = 0.25 (silica gel, acetone), m.p. 149–151 °C. IR (KBr): ν

˜

f

= 3084 (m, CH_arom.), 3069 (m, CH_arom.), 3045 (m, CH_arom.), 2964

(s, CH_aliph.), 2927 (vs, CH_aliph.), 2854 (s, CH_aliph.), 1659 (vs, C=N),

1643 (s, C=N), 1607 (vs, C=C_arom.), 1574 (s, C=C_arom.), 1490 (m),

1477 (m), 1448 (s), 1387 (w), 1355 (w), 1315 (m), 1305 (m), 1275

(m), 1163 (m), 1155 (m), 1123 (s), 1101 (m), 1043 (m), 1018 (m),

935 (w), 924 (w), 889 (w), 852 (w), 792 (m), 773 (w), 723 (vs), 694

202 °C (dec.). IR (KBr): ν = 3065 (s, CH_arom.), 3055 (s, CH_arom.),

˜

3042 (s, CH_arom.), 3024 (s, CH_arom.), 2999 (s, CH_aliph.), 2962 (s,

CH_aliph.), 2926 (s, CH_aliph.), 2854 (s, CH_aliph.), 1603 (vs, C=N), 1568

(s, C=C_arom.), 1504 (vs, C=C_arom.), 1489 (vs), 1474 (vs), 1452 (s),

1394 (s), 1369 (s), 1358 (s), 1315 (vs), 1290 (s), 1250 (m), 1209 (s),

1196 (s), 1173 (m), 1119 (m), 1099 (m), 1067 (m), 1024 (m), 1005

(m), 937 (m), 914 (w), 872 (w), 845 (w), 783 (s), 770 (s), 733 (s),

712 (m), 700 (s), 696 (s) cm^–1. ¹H NMR (300 MHz, CDCl₃): δ =

1.16 (s, 9 H, CH₃), 6.65 (m, 2 H, CH_arom.), 6.88–7.01 (m, 3 H,

CH_arom.), 7.09–7.14 (m, 2 H, CH_arom.), 7.22–7.27 (m, 2 H,

CH_arom.), 7.35–7.41 (m, 3 H, CH_arom.), 7.41–7.47 (m, 2 H,

1

(s) cm^–1. H NMR (600 MHz, CDCl₃): δ = 0.35 (br., 0.7 H, CH₂),

0.97–1.07 (m, 4.2 H, CH₂), 1.16 (br., 2.8 H, CH₂); 1.26 [s, 9 H,

H(15)], 1.31–1.36 (m, 2.6 H, CH₂), 1.46–1.47 (m, 0.9 H, CH₂), 1.51

[s, 2.7 H, H(15Ј)], 1.62 (br., 1.8 H, CH₂), 3.08 [br., 1 H, H(16)],

3.98–4.03 [m, 0.3 H, H(16Ј)], 7.16 (br., 2 H, CH_arom.), 7.23–7.25

(m, 1 H, CH_arom.), 7.28–7.34 (m, 1.2 H, CH_arom.), 7.34–7.40 (m,

6.1 H, CH_arom.), 7.42–7.44 (m, 1.1 H, CH_arom.), 7.47–7.52 (m, 1 H,

CH_arom.), 7.54–7.56 [m, 2 H, H(5)], 7.61–7.62 [m, 0.6 H, H(5Ј)],

7.65–7.66 [m, 0.6 H, H(8Ј)], 7.88–7.90 [m, 2 H, H(11)], 8.17–8.19

[m, 0.6 H, H(11Ј)] ppm. ¹³C NMR (150.84 MHz, CDCl₃): δ = 25.1,

(CH₂), 25.7 (CH₂), 27.1 (CH₂), 29.3 [C(15)], 29.9 [C(15Ј)], 32.8

(CH₂), 39.4 [C(14)], 40.1 [C(14Ј)], 56.6 [C(16)], 59.4 [C(16Ј)], 83.3

[C(3Ј)], 119.9 [C(5Ј)], 120.2 [C(5)], 126.7 (C8Ј)) , 127.6, 127.7, 127.8,

127.9, 128.3, 128.6, 129.2 (C_arom.), 129.8 [C_arom., C(10Ј)], 131.0

[C_arom., C(10)], 132.2 [C(9)], 132.6 (C_arom.), 137.7 [C(4)], 138.8

[C(9Ј)], 150.8 [C(4Ј)], 156.3 [C(2)], 159.9 [C(2Ј)], 161.9 [C(3)], 168.3

[C(1)], 171.9 [C(1Ј)] ppm. MS (70 eV): m/z (%) = 447 (66) [M⁺],

390 (36) [M⁺– tBu], 308 (58) [M⁺– tBu – C₆H₁₀], 267 (100)

[C₁₃H₈NCPh⁺], 205 (35) [C₁₃H₈NCNH⁺], 164 (43) [C₁₃H₈⁺], 84

(41) [C₆H₁₂⁺]. C₃₁H₃₃N₃(447.53): calcd. C 83.18 H 7.43 N 9.39;

found C 83.08 H 7.35 N 9.31.

CH_arom.), 7.51–7.53 (m, 2 H, CH_arom.), 8.30–8.33 (m, 2 H, CH_arom.

)

ppm. ¹³C NMR (75.47 MHz, CDCl₃): δ = 30.4 (CH₃), 40.8

[C(CH₃)₃], 86.0 (C_quart.), 119.6, 125.9, 127.5, 127.7, 127.9, 128.0,

128.2, 129.3, 130.1, 130.5 (C_arom.), 137.6 (i-C_arom.), 139.3 (i-C_arom.),

140.7 (i-C_arom.), 148.3 (i-C_arom.), 161.4 (C=N), 171.5 (C=N) ppm.

MS (70 eV): m/z (%) = 441 (80) [M⁺], 384 (100) [M⁺–tBu], 281

(24) [M⁺–PhNCtBu], 267 (40) [C₁₃H₈NCPh⁺], 164 (54) [C₁₃H₈⁺],

104 (25) [PhCNH⁺], 57 (10) [tBu⁺]. C₃₁H₂₇N₃(441.55) HR MS:

calcd. 442.2283; found 442.2303 [C₃₁H₂₇N₃+H⁺].

6-(Adamantan-2-ylidene)-2-tert-butyl-1-cyclohexyl-4-phenyl-1,3,5-

triazahexa-1,3,5-triene (6a): From 1e (0.87 g, 3.00 mmol) and 2-ad-

amantanone (0.45 g, 3.00 mmol). Column chromatography (ace-

tone). Yield 0.47 g (1.10 mmol, 38%), colorless solid. R_f(DC) =

0.09 (silica gel, acetone), m.p. 151–152 °C. IR (KBr): ν = 3080 (m,

˜

CH_arom.), 3053 (m, CH_arom.), 3026 (m, CH_arom.), 2984 (s, CH_aliph.),

2924 (vs, CH_aliph.), 2854 (vs, CH_aliph.), 1704 (m), 1666 (vs, C=N),

1609 (vs, C=C_arom.), 1576 (s, C=C_arom.), 1526 (m, C=C_arom.), 1479

(m), 1450 (s), 1385 (m), 1364 (s), 1350 (s), 1311 (m), 1288 (m), 1267

(m), 1252 (s), 1232 (m), 1153 (s), 1134 (s), 1069 (s), 1026 (m), 1018

(m), 997 (m), 951 (m), 890 (s), 864 (m), 845 (m), 829 (m), 795 (m),

777 (s), 719 (s), 698 (s) cm^–1. ¹H NMR (300 MHz, CDCl₃): δ =

1.17–1.23 (m, 13 H, CH₃/CH₂), 1.74–1.96 (m, 18 H, CH_2,Ad./CH₂/

CH_Ad.), 2.58 (br., 2 H, CH_Ad.), 3.06 (br., 1 H, CH), 7.35 (m, 3 H,

CH_{a r o m .}), 7.76–7.80 (m, 2 H, CH_{a r o m .}) ppm. ^{1 3}C NMR

(75.47 MHz, CDCl₃): δ = 25.1 (CH₂), 26.1 (CH₂), 27.3 (CH_Ad.),

29.5 [C(CH₃)₃], 36.2 (CH₂), 38.9 (CH_2Ad.), 41.1 [C(CH₃)₃/CH_Ad.

]

57.1 (CH), 127.7, 128.3, 130.4 (C_arom.), 135.7 (i-C_arom.), 155.7

(C=N), 168.8 (C=N), 181.5 (C=N) ppm. MS (70 eV): m/z (%) =

417 (2) [M⁺], 360 (15) [M⁺–tBu], 334 (11) [M⁺–C₆H₁₁], 278 (29)

[ 3 3 4 – t B u ⁺+ 1 ] , 2 6 9 ( 1 0 0 ) [ M ⁺– N C _{1 0}H _{1 4}] , 2 3 7 ( 7 7 )

[PhCNC₁₀H₁₄⁺], 165 (18) [C₆H₁₁NCtBu⁺– 1], 84 (44) [C₆H₁₂⁺].

C₂₈H₃₉N₃(417.60): calcd. C 80.53 H 9.41 N 10.03; found C 80.38

H 9.35 N 9.94.

Scheme 13. Numbering of 6b/6bЈ for NMR assignment.

X-ray Crystal Structure Analysis of 6b:^[21]Formula C₃₁H₃₃N₃, M

= 447.60, yellow crystal 0.50×0.35×0.25 mm, a = 9.765(2), b =

10.640(2), c = 14.606(4) Å, α = 94.58(3), β = 108.17(2), γ =

113.45(1)°, V = 1286.1(5) Å³, ρ_{ca lc d.}= 1.156 g cm^{– 3}, µ =

X-ray Crystal Structure Analysis of 6a:^[21]Formula C₂₈H₃₉N₃, M = 0.517 mm^–1, empirical absorption correction (0.782 Յ T Յ 0.882),

¯

Z = 2, triclinic, space group P1 (No. 2), λ = 1.54178 Å, T = 223 K,

417.62, colorless crystal 0.25×0.20×0.15 mm, a = 10.937(1), b =

11.182(2), c = 20.010(5) Å, β = 90.91(1)°, V = 2446.9(8) Å³, ρ_calcd.ω/2θ scans, 5543 reflections collected ( h, –k, l), [(sinθ)/λ] =

= 1.134 gcm^–3, µ = 0.501 mm^–1, empirical absorption correction

(0.885 Յ T Յ 0.929), Z = 4, monoclinic, space group P2₁(No. 4),

0.62 Å^–1, 5247 independent (R_int= 0.037) and 4145 observed reflec-

tions [I Ն 2σ(I)], 310 refined parameters, R = 0.057, wR₂= 0.164,

3932

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Eur. J. Org. Chem. 2006, 3923–3937

Triazapentadienes as Building Blocks for Dihydrotriazines and Oligonitriles

FULL PAPER

max. residual electron density 0.29 (–0.35) e·Å^–3, hydrogen atoms

m.p. 198 °C. IR (KBr): ν = 3315 (s, NH), 3134 (w, CH_arom.), 3063

˜

calculated and refined as riding atoms.

(m, CH_arom.), 3028 (w, CH_arom.), 2922 (w, CH_aliph.), 1649 (vs, C=O/

C=N), 1607 (C=C_arom.), 1572 (vs, C=C_arom.), 1497 (C=C_arom.),

1441 (vs), 1354 (m), 1329 (s), 1315 (s), 1265 (s), 1177 (m), 1161 (m),

1094 (m), 1045 (m), 1016 (m), 914 (m), 899 (m), 847 (m), 758 (s),

2-tert-Butyl-1-cyclohexyl-4,6,6-triphenyl-1,3,5-triazahexa-1,3,5-tri-

ene (6c) and 6-tert-Butyl-1-cyclohexyl-2,2,4-triphenyl-1,2-dihydro-

1,3,5-triazine (6cЈ): From 1e (0.86 g, 3.00 mmol) and benzophenone

(0.55 g, 3.00 mmol). Column chromatography (acetone). Yield

0.21 g (0.50 mmol, 15%), yellow oil, slowly crystallizing to give a

colorless solid. R_f(DC) = 0.13 (silica gel, acetone), m.p 77–83 °C.

It was difficult to differentiate the open-chain structure from a pos-

sible cyclic form by spectroscopic means. Comparisons with the

other compounds 6 indicate equilibrium of the tautomers in solu-

1

690 (s) cm^–1. H NMR (300 MHz, [D₆]DMSO): δ = 2.37 (s, 3 H,

CH₃), 7.08–7.12 (m, 1 H, CH_arom.), 7.17–7.30 (m, 6 H, CH_arom.),

7.40–7.69 (m, 6 H, CH_arom.), 7.60–7.69 (m, 4 H, CH_arom.), 7.95 (m,

2 H, CH_arom.), 9.98 (s, 1 H, NH) ppm. ¹³C NMR (75.47 MHz,

[D₆]DMSO): δ = 22.0 (CH₃), 121.7, 124.6, 128.7, 128.8, 129.1,

129.3, 129.5, 131.5, 132.1, 133.0 (C_arom.), 134.5 (i-C_arom.), 136.8 (i-

C

_arom.), 140.5 (i-C_arom.), 142.8 (i-C_arom.), 157.1 (C=N), 162.3

tion (Scheme 14). IR (KBr): ν = 3082 (m, CH_arom.), 3057 (m,

˜

(C=N), 179.4 (C=O) ppm. MS (70 eV): m/z (%) = 417 (44) [M⁺],

194 (38) [(Ph)₂CN₂⁺], 180 (85) [PhCNPh⁺], 119 (100) [TolCO⁺], 105

(77) [PhCNH₂⁺], 91 (25) [Tol⁺], 77 (43) [Ph⁺]. C₂₈H₂₃N₃O (417.49):

calcd. C 80.55 H 5.55 N 10.06; found C 80.03 H 5.58 N 10.01.

CH_arom.), 3028 (m, CH_arom.), 2962 (s, CH_aliph.), 2930 (s, CH_aliph.),

2854 (m, CH_aliph.), 1637 (m, C=N), 1603 (s, C=C_arom.), 1570 (s,

C=C_arom.), 1516 (s, C=C_arom.), 1489 (s), 1448 (s), 1400 (m), 1367

(m), 1325 (s), 1296 (m), 1263 (m), 1223 (m), 1184 (m), 1167 (m),

1115 (m), 1076 (m), 1028 (m), 995 (m), 933 (w), 895 (w), 870 (m),

779 (m), 754 (m), 746 (m), 704 (vs) cm^–1. ¹H NMR (600 MHz,

[D₈]THF): δ = 0.84–0.91 (m, 0.8 H, CH₂), 1.01 [s, 9 H, H(13)],

1.13–1.20 (m, 5.8 H, CH₂), 1.22–1.34 (m, 3.2 H, CH₂), 1.46 [s, 3.6

H, H(13Ј)], 1.46 (br., 1.8 H, CH₂), 1.64 (br., 2.4 H, CH₂), 2.77 [br.,

X-ray Crystal Structure Analysis of 8a:^[21]Formula C₂₈H₂₃N₃O, M

= 417.49, colorless crystal 0.40×0.03×0.03 mm, a = 24.460(1), b

= 19.060(1), c = 9.791(1) Å, V = 4564.6(6) Å³, ρ_calcd.= 1.215 gcm^–3,

µ = 0.075 mm^–1, empirical absorption correction (0.971 Յ T Յ

0.998), Z = 8, orthorhombic, space group Aba2 (No. 41), λ =

0.71073 Å, T = 198 K, ω and φ scans, 12490 reflections collected

( h, k, l), [(sinθ)/λ] = 0.59 Å^–1, 3923 independent (R_int= 0.113)

and 2568 observed reflections [I Ն 2σ(I)], 295 refined parameters,

R = 0.062, wR₂= 0.135, max. residual electron density 0.14 (–0.19)

e·Å^–3, hydrogen atom at N6 from difference Fourier map, other

calculated and refined as riding atoms.

1 H, H(14)], 3.44–3.49 [m, 0.4 H, H(14Ј)], 7.14 (br., 1.4 H, CH_arom.

)

7.34–7.38 (m, 7.6 H, CH_arom.), 7.40–7.41 (m, 1.2 H, CH_arom.), 7.43–

7.44 (m, 8 H, CH_arom.), 7.77–7.78 [m, 2 H, H(9)], 8.35–8.37 [m, 0.8

H, H(9Ј)] ppm. ¹³C NMR (150.84 MHz, [D₈]THF): δ = 27.0 (CH₂),

28.0 (CH₂), 29.2 (CH₂), 30.4 [C(13)], 31.6 [C(13Ј)], 35.1 (CH₂), 40.6

[C(12)], 41.1 [C(12Ј)], 57.5 [C(14)], 63.1 [C(14Ј)], 80.3 [C(3Ј)], 129.3,

129.4, 129.6, 129.9, 130.1, 131.0, 131.6, 132.1, 132.4 (C_arom.),138.5

[C(4Ј)], 138.7 [C(4)], 138.9 [C(4Ј)], 156.8 [C(2)], 162.3 [C(2Ј)], 167.8

[C(3)], 167.9 [C(1)], 179.6 [C(1Ј)] ppm. MS [70 eV]: m/z (%) = 449

(26) [M⁺], 392 (19) [M⁺–tBu], 310 (33) [392⁺–C₆H₁₁+1], 269 (100)

[M⁺–Ph₂CN], 165 (35) [C₆H₁₁NCtBu⁺–1], 104 (15) [PhCNH⁺], 84

(34) [C₆H₁₂⁺]. C₃₁H₃₅N₃(449.61): calcd. C 82.81 H 7.85 N 9.35;

found C 82.46 H 8.03 N 8.88.

6-tert-Butyl-7-cyclopentyl-2-(4-methylphenyl)-4-phenyl-1-oxa-3,5,7-

triazahepta-1,3,5-triene (8b): From 1f (950 mg, 3.5 mmol) and 4-

methylbenzoyl chloride (7a) (541 mg, 3.5 mmol). Purification by

dissolving the crude product in a small amount of hot ethyl acetate

and precipitation using n-heptane. Yield 0.92 g (2.40 mmol, 67%),

colorless solid, m.p 116 °C. IR (KBr): ν = 3348 (s, NH), 3329 (s,

˜

NH), 3082 (m, CH_arom.), 3053 (m, CH_arom.), 3028 (m, CH_arom.),

2959 (s, CH_aliph.), 2914 (m, CH_aliph.), 2870 (m, CH_aliph.), 1664 (vs,

C=N/C=O), 1624 (vs, C=C_arom.), 1603 (vs, C=C_arom.), 1572 (s),

1558 (s), 1522 (vs), 1447 (s), 1400 (s), 1381 (s), 1360 (m), 1313 (s),

1271 (s), 1222 (s), 1211 (s), 1177 (s), 1096 (m), 1067 (m), 1049 (m),

1018 (m), 912 (m), 847 (m), 770 (s), 698 (s) cm^–1¹H NMR

.

(300 MHz, CDCl₃): δ = 1.12–1.18 [m, 11 H, C(CH₃)₃/CH₂], 1.40–

1.64 (m, 6 H, CH₂), 2.37 (s, 3 H, CH₃), 3.90 (m, 1 H, CH), 7.15–

7.18 (m, 2 H, CH_arom.), 7.41–7.46 (m, 3 H, CH_arom.), 7.94–7.96

(m, 2 H, CH_arom.), 8.05–8.07 (m, 2 H, CH_arom.) ppm. ¹³C NMR

(75.47 MHz, CDCl₃): δ = 21.5 (CH₃), 23.8 (CH₂), 28.5 [C(CH₃)₃],

33.4 (CH₂), 38.9 [C(CH)₃]₃, 53.5 (CH), 128.0, 128.5, 128.6, 129.4,

130.8, 133.1 (C_arom.), 136.5 (i-C_arom.), 141.9 (i-C_arom.), 158.4 (C=N),

162.3 (C=N), 179.7 (C=O) ppm. MS (70 eV): m/z (%) = 389 (9)

[M⁺], 306 (18) [M⁺– C₅H₉N], 270 (22) [M⁺– TolCO], 223 (11)

[PhCNCTolOH⁺], 187 (13), 167 (24) [C₅H₉NHCtBuN⁺], 151 (33)

[C₅H₈NCtBu⁺], 119 (100) [TolCO⁺], 104 (51) [PhCNH⁺], 91 (25)

[Tol⁺], 84 (49) [C₅H₉NH⁺], 57 (21) [tBu⁺]. C₂₅H₃₁N₃O (389.51):

calcd. C 77.08 H 8.02 N 10.79; found C 76.93 H 7.79 N 10.68.

Scheme 14. Numbering of 6c/6cЈ for NMR assignment.

General Procedure for the Acylation of 1,3,5-Triazapenta-1,3-dienes:

Triazapentadiene 1 (3.50 mmol), triethylamine (3.85 mmol) and a

small amount of 4-(dimethylamino)pyridine (DMAP) were dis-

solved in 20 mL of dichloromethane. At 0 °C acid chloride 7

(3.50 mmol) was added dropwise. After stirring at room tempera-

ture for 2 h, the reaction mixture was treated with 20 mL of water.

The aqueous layer was extracted twice with dichloromethane. The

combined organic layers were dried with magnesium sulfate. After

evaporation of the solvent, the crude product is purified by

recrystallization.

2,6-Di-tert-butyl-7-cyclopentyl-4-phenyl-1-oxa-3,5,7-triazahepta-

1,3,5-triene (8c): From 1f (0.95 g, 3.50 mmol) and pivaloyl chloride

(7b) (0.42 g, 3.50 mmol). Recrystallization from ethyl acetate/n-hep-

tane. Yield 0.70 g (1.97 mmol, 56%), colorless solid, m.p 144 °C.

IR (KBr): ν = 3369 (s, NH), 3065 (m, CH_arom.), 3028 (m, CH_arom.),

˜

2-(4-Methylphenyl)-4,6,8-triphenyl-1-oxa-3,5,7-triazahepta-1,3,5-tri- 2961 (s, CH_aliph.), 2914 (m, CH_aliph.), 2868 (m, CH_aliph.), 1668 (vs,

ene (8a): From 1a^[1,2](1.05 g, 3.50 mmol) and 4-methylbenzoyl

chloride (7a) (0.54 g, 3.50 mmol). Byproducts were removed by ex-

traction with 20 mL of boiling ethanol. The residue was filtered off

und dried in vacuo. Yield 0.67 g (1.60 mmol, 46%), colorless solid,

C=N/C=O), 1639 (s, C=C_arom.), 1591 (vs, C=C_arom.), 1566 (vs,

C=C_arom.), 1535 (s), 1477 (s), 1448 (m), 1389 (m), 1362 (m), 1335

(s), 1275 (m), 1220 (m), 1146 (s), 1084 (m), 1072 (m), 1028 (m), 906

1

(m), 860 (m), 827 (m), 775 (m), 740 (m), 692 (m) cm^–1. H NMR

Eur. J. Org. Chem. 2006, 3923–3937

www.eurjoc.org

3933

N. Heße, R. Fröhlich, B. Wibbeling, E.-U. Würthwein

FULL PAPER

(360 MHz, [D₆]DMSO, 373 K): δ = 1.23 (s, 9 H, CH₃), 1.26 (s, 9 C=C_arom.), 1518 (s), 1489 (s), 1481 (s), 1448 (s), 1396 (m), 1364 (m),

H, CH₃), 1.40 (br., 4 H, CH₂), 1.64 (br., 4 H, CH₂), 3.99 (m, 1 H, 1327 (s), 1313 (s), 1286 (s), 1269 (s), 1227 (m), 1207 (s), 1167 (m),

CH), 6.32 (br., 1 H, NH), 7.42–7.47 (m, 3 H, CH_arom.), 7.86–7.88 1045 (m), 1026 (m), 926 (m), 905 (m), 895 (m), 831 (m), 819 (m),

1

(m, 2 H, CH_arom.) ppm. ¹³C NMR (90.56 MHz, [D₆]DMSO, 770 (m), 746 (m), 696 (vs) cm^–1. H NMR (300 MHz, CDCl₃): δ =

373 K): δ = 23.9 (CH₂), 27.7 (CH₃), 28.6 (CH₃), 32.7 (CH₂), 39.3 0.63–0.71 (m, 2 H, CH₂), 0.84 (s, 9 H, CH₃), 0.94–1.15 (m, 4 H,

[C(CH₃)₃], 41.2 [C(CH₃)₃], 53.6 (CH), 128.1 (C_arom.), 128.3 CH₂), 1.21–1.30 (m, 2 H, CH₂), 3.11 (br., 1 H, CH), 4.33 (br., 1 H,

(o-C_arom.), 130.6 (C_arom.), 137.4 (i-C_arom.), 156.7 (C=N), 162.5

NH), 6.83–6.88 (m, 1 H, CH_arom.), 7.12–7.17 (m, 2 H, CH_arom.),

(C=N), 192.0 (C=O) ppm. MS (70 eV): m/z (%) = 355 (1) [M⁺], 7.23–7.34 (m, 8 H, CH_arom.), 7.72–7.74 (m, 2 H, CH_arom), 7.87 (br.,

298 (100) [M⁺–tBu], 127 (13), 84 (15), [C₅H₉NH⁺], 57 (25) [tBu⁺]. 2 H, CH_arom.) ppm. ¹³C NMR (75.47 MHz, CDCl₃): δ = 23.3

C₂₂H₃₃N₃O (355.49): calcd. C 74.32 H 9.36 N 11.82; found C 74.13

H 9.25 N 11.85.

(CH₂), 28.4 (CH₃), 33.3 (CH₂), 38.5 (CCH₃), 53.3 (CH), 122.7,

123.1, 127.7, 127.9, 128.0, 128.2, 129.3, 130.2 (C_arom.), 136.6 (i-

C

_arom.), 137.6 (i-C_arom.), 149.7 (C=N), 158.1 (C=N), 159.4 (C=N)

6-tert-Butyl-7-cyclopentyl-2-(4-methylphenyl)-3,4-diphenyl-1-oxa-

3,5,7-triazahepta-1,4,6-triene (8d): Compound 1h (0.52 g,

1.50 mmol) was dissolved in 20 mL of dry THF. At –78 °C nBuLi

(1.9 mL, 3.00 mmol; 1.6  solution in n-hexane) was added drop-

wise. After stirring at 0 °C for 15 min, the yellow reaction mixture

was cooled to –78 °C and treated with 4-methylbenzoyl chloride

(7a) (0.46 g, 3.00 mmol). Then, the reaction mixture was warmed

in an ice bath and stirred at room temperature overnight. The solu-

tion was washed with 20 mL of water. The aqueous layer was ex-

tracted three times with dichloromethane. The combined organic

layers were dried with magnesium sulfate. After evaporation of the

solvent, the crude product was purified by column chromatography

[silica gel, petroleum ether/TMBE, 2:1). Yield 322 mg (0.70 mmol,

46%), light yellow solid. R_f(DC) = 0.15 (silica gel, petroleum ether/

ppm. MS (70 eV): m/z (%) = 450 (64) [M⁺], 283 (17) [Ph₃C₂N₂⁺],

255 (10) [PhCNCtBuNC₅H₉⁺], 180 (100) [PhCNPh⁺], 151 (10)

[tBuCNC₅H₈⁺], 104 (139) [PhCNH⁺], 77 (39) [Ph⁺]. C₃₀H₃₄N₄

(450.60): calcd. C 79.96 H 7.60 N 12.43; found C 79.73 H 7.20 N

12.39.

X-ray Crystal Structure Analysis of 9a:^[21]Formula C₃₀H₃₄N₄, M =

450.61, light yellow crystal 0.45×0.30×0.20 mm, a = 10.460(1), b

= 17.769(1), c = 14.653(1) Å, β = 109.91(1)°, V = 2560.7(3) Å³,

ρ_calcd.= 1.169 gcm^–3, µ = 0.069 mm^–1, empirical absorption correc-

tion (0.969 Յ T Յ 0.993), Z = 4, monoclinic, space group P2₁/c

(No. 14), λ = 0.71073 Å, T = 198 K, ω and φ scans, 16420 reflec-

tions collected ( h, k, l), [(sinθ)/λ] = 0.66 Å^–1, 6113 independent

(R_int= 0.045) and 4389 observed reflections [I Ն 2σ(I)], 313 refined

parameters, R = 0.052, wR₂= 0.133, max. residual electron density

0.23 (–0.18) e·Å^–3, hydrogen atom at N1 from difference Fourier

map, other calculated and refined as riding atoms.

TBME, 2:2), m.p. 99–108 °C. IR (KBr): ν = 3074 (w, CH_arom.),

˜

2939 (vs, CH_aliph.), 2852 (m, CH_aliph.), 1657 (vs, C=O), 1635 (vs,

C=N), 1483 (s, C=C_arom.), 1439 (m), 1400 (w), 1330 (vs), 1296 (m),

1261 (s), 1174 (m), 1104 (m), 1043 (w), 1009 (w), 835 (m), 748 (s)

cm^–1. ¹H NMR (600 MHz, CDCl₃): δ = 0.87 [s, 9 H, C(CH₃)₃],

1.91–1.24 [m, 1 H, CH₂], 1.35–1.41 (m, 1 H, CH₂), 1.44–1.52 (m,

3 H, CH₂), 1.59–1.62 (m, 1 H, CH₂), 1.69–1.73 (m, 2 H, CH₂), 2.28

General Procedure for the Synthesis of 1,3,5,7-Tetraazahepta-

1,3,5,7-trienes 9b,c: Under argon a solution of 1 (2.00 mmol) in

8 mL of anhydrous diethyl ether was treated with imidoyl chloride

2 (1.1 equiv.). After stirring at room temperature for 1 h, the reac-

tion mixture was heated to reflux for 2 h. The resulting colorless

precipitate was filtered off and added to 20 mL of a 2  sodium

hydroxide solution. The suspension was extracted with three por-

tions of 30 mL of dichloromethane. After drying of the combined

organic extracts, the solvent was removed in vacuo. Purification

was achieved by column chromatography (neutral alumina, Alox

N, activity 1, pentane/TBME, 2:1 + 4% triethylamine).

3

(s, 3 H, CH₃), 3.60 (quint, J = 6.0 Hz, 1 H, CH), 7.01–7.02 (m, 2

H, CH_arom.), 7.19–7.22 (m, 3 H, CH_arom.), 7.28–7.33 (m, 5 H,

CH_arom.), 7.46–7.47 (m, 2 H, CH_arom.), 7.62–7.63 (m, 2 H, CH_arom.

)

ppm. ¹³C NMR (150.84 MHz, CDCl₃): δ = 21.4 (CH₃), 24.4 (CH₂),

24.7 (CH₂), 28.6 [C(CH₃)₃], 33.3 (CH₂), 33.5 (CH₂), 38.9 [C(CH₃)

₃], 59.4 (CH), 127.1, 127.9, 128.3, 128.5, 128.7, 129.1, 129.3, 130.5,

132.8 (C_arom.), 135.4, 141.6, 142.0 (i-C_arom.), 152.5 (C=N), 164.6

(C=N), 172.0 (C=O) ppm. MS (70 eV): m/z (%) = 465 (4) [M⁺],

255 (54) [C₅H₉NCtBuNCPh⁺], 211 (12) [PhNCTolH⁺], 180 (83)

[PhCNPh⁺], 152 (34) [C₅H₉NCtBu⁺], 119 (100) [TolCO⁺], 84 (60)

[C₅H₉NH⁺], 57 (48) [tBu⁺]. C₃₁H₃₅N₃O (465.61): calcd. C 79.96 H

7.58 N 9.02; found C 80.02 H 7.44 N 9.04.

2,6-Di-tert-butyl-1,7-dicyclohexyl-4-phenyl-1,3,5,7-tetraazahepta-

1,3,5-triene (9b): From 1e (0.71 g, 2.50 mmol) and 2e (0.56 g).^[23]

Colorless oil, slowly crystallizing. Yield 0.67 g (1.50 mmol, 59%).

R_f(DC) = 0.24 (silica gel, pentane/TBME, 2:1 + 4% triethylamine),

m.p. 83–85 °C. IR (KBr): ν = 3431 (s, NH), 3283 (s, NH), 3063 (m,

˜

6-tert-Butyl-7-cyclopentyl-1,3,5-triphenyl-1,3,5,7-tetraazahepta-

1,3,5-triene (9a): Under argon at 0 °C, 1a (1090 mg, 3.60 mmol),^[1,2]

dissolved in 15 mL of dry THF, was added dropwise to a solution

of KOtBu (0.41 g, 3.60 mmol) in 5 mL of dry THF. After stirring

for 5 min with ice cooling, the reaction mixture was stirred at room

temperature for 15 min. After cooling to 0 °C, the reaction mixture

was treated with a solution of 2f (676 mg, 3.6 mmol) in THF

(10 mL) and then stirred at room temperature overnight. The reac-

tion mixture was diluted by adding 30 mL of dichloromethane and

then washed with water. The layers were separated, and the aque-

ous layer was extracted twice with dichloromethane. The combined

organic layers were dried with magnesium sulfate, and the solvent

was evaporated. The residue was purified by column chromatog-

raphy (silica gel, pentane/TBME, 10:1 + 2% triethylamine). Yield

0.93 g (2.10 mmol, 57%), yellow solid. R_f(DC) = 0.13 (silica gel,

pentane/TBME, 10:1 + 2% triethylamine), m.p. 153 °C. IR (KBr):

CH_arom.) 3026 (m, CH_arom.), 2966 (s, CH_aliph.), 2930 (vs, CH_aliph.),

2854 (s, CH_aliph.), 1647 (vs, C=N), 1614 (vs, C=C_arom.), 1589 (vs,

C=C_arom.), 1574 (vs), 1516 (vs), 1479 (s), 1448 (s), 1398 (m), 1389

(m), 1367 (s), 1329 (s), 1315 (s), 1275 (s), 1258 (m), 1227 (m), 1161

(s), 1136 (s), 1090 (m), 1063 (m), 1026 (m), 966 (m), 941 (m), 889

(m), 864 (m), 802 (m), 770 (m), 723 (m), 694 (s) cm^–1. ¹H NMR

(300 MHz, CDCl₃): δ = 1.07 (br., 7 H, CH₂), 1.22 (m, 20 H, CH₃/

CH₂), 1.48–1.57 (m, 11 H, CH₂), 3.23 (br., 2 H, CH), 7.32–7.36

(m, 3 H, CH_arom.), 7.65–7.69 (m, 2 H, CH_arom.) ppm. ¹³C NMR

(75.47 MHz, CDCl₃): δ = 25.0 (CH₂), 25.5 (CH₂), 27.5 (CH₂), 29.0

(CH₃), 33.1 (CH₂), 33.9 (CH₂), 38.8 [C(CH₃)₃], 48.0 (CH), 127.5

(C_arom.), 128.1 (o-C_arom.), 129.4 (C_arom.), 137.6 (i-C_arom.), 155.9

(C=N), 177.4 (C=N) ppm. MS (70 eV): m/z (%) = 450 (14) [M⁺],

393 (97) [M⁺– tBu], 311 (32) [M⁺– tBu – C₆H₁₀], 269 (89) [M⁺–

(HNCtBuNC₆H₁₁)], 173 (31) [PhCNCtBuH⁺], 163 (22), 129 (18),

110 (51), 104 (28) [PhCNH⁺], 84 (100) [C₆H₁₂⁺], 57 (68) [tBu⁺]. HR

MS: calcd. 451.3801; found 451.3019 [C₂₉H₄₆N₄+H⁺]. C₂₉H₄₆N₄

ν = 3389 (s, NH), 3074 (m, CH_arom.), 3061 (m, CH_arom.), 3026 (m,

˜

CH_arom.), 2964 (s, CH_aliph.), 2931 (s, CH_aliph), 2866 (s, CH_aliph.), (450.67): calcd. C 77.28, H 10.29, N 12.43; found C 76.51, H 10.34,

1657 (vs, C=N), 1597 (vs, C=C_arom.), 1585 (vs, C=C_arom.), 1568 (vs, N 11.71.

3934

www.eurjoc.org

Eur. J. Org. Chem. 2006, 3923–3937

Triazapentadienes as Building Blocks for Dihydrotriazines and Oligonitriles

FULL PAPER

X-ray Crystal Structure Analysis of 9b:^[21]Formula C₂₉H₄₆N₄·

1/3H₃OCl, M = 486.86, colorless crystal 0.40×0.30×0.03 mm, a =

CH₂), 3.45 (br., 1 H, CH), 7.26–7.51 (m, 9 H, CH_arom.), 7.69–7.72

(m, 2 H, CH_arom.), 7.92 (m, 2 H, CH_arom.), 8.10 (m, 2 H, CH_arom.

)

17.157(1), c = 52.859(2) Å, V = 13475.1(12) Å³, ρ_calcd.

=

ppm. ¹³C NMR (75.47 MHz, CDCl₃): δ = 23.6 (CH₂), 28.4 (CH₃),

33.4 (CH₂), 38.7 (CCH₃), 53.6 (CH), 127.9, 128.0, 128.3, 128.8,

129.4, 130.5, 130.7 (C_arom.), 131.8 (i-C_arom.), 134.8 (i-C_arom.), 134.9

(i-C_arom.), 136.2 (i-C_arom.), 159.8 (C=N), 160.7 (C=N), 163.4

(C=N), 179.9 (C=O) ppm. MS (70 eV): m/z (%) = 478 (22) [M⁺],

312 (22) [Ph₃C₃N₂O⁺], 289 (14), 255 (12) [C₅H₉NCtBuNCPh⁺], 180

(26) [PhCNPh⁺], 146 (32), 105 (100) [PhCO⁺], 84 (56) [C₅H₉NH⁺].

C₃₁H₃₄N₄O (478.61): calcd. C 77.79 H 7.16 N 11.71, found C 77.64

H 7.02 N 11.73.

1.040 g cm^–3, µ = 0.736 mm^–1, empirical absorption correction

¯

(0.757 Յ T Յ 0.978), Z = 18, trigonal, space group R3 (No. 148),

λ = 1.54178 Å, T = 223 K, ω and φ scans, 8577 reflections collected

( h, k, l), [(sinθ)/λ] = 0.59 Å^–1, 5044 independent (R_int= 0.038)

and 2785 observed reflections [I Ն 2σ(I)], 317 refined parameters,

R = 0.055, wR₂= 0.148, max. residual electron density 0.23

(–0.226) e·Å^–3, hydrogen atom at N7 from difference Fourier map,

other calculated and refined as riding atoms.

X-ray Crystal Structure Analysis of 11a:^[21]Formula C₃₁H₃₄N₄O,

M = 478.62, colorless crystal 0.35×0.35×0.30 mm, a = 11.591(2),

b = 19.038(2), c = 12.397(2) Å, β = 100.71(1)°, V = 2688.0(7) Å³,

ρ_calcd.= 1.183 gcm^–3, µ = 0.566 mm^–1, empirical absorption correc-

tion (0.826 Յ T Յ 0.849), Z = 4, monoclinic, space group P2₁/n

(No. 14), λ = 1.54178 Å, T = 223 K, ω/2θ scans, 5796 reflections

collected ( h, –k, –l), [(sinθ)/λ] = 0.62 Å^–1, 5477 independent (R_int

= 0.020) and 4208 observed reflections [I Ն 2σ(I)], 332 refined pa-

rameters, R = 0.058, wR₂= 0.188, max. residual electron density

0.49 (–0.45) e·Å^–3, hydrogen atom at N1 from difference Fourier

map, other calculated and refined as riding atoms.

2,6-Di-tert-butyl-1,7-diisopropyl-4-phenyl-1,3,5,7-tetraazahepta-

1,3,5-triene (9c): From 1g (0.42 g, 1.72 mmol) and 2g (0.31 g,

1.72 mmol).^[24]Yield 0.24 mg (0.60 mmol, 37 %), colorless solid.

R_f(DC) = 0.14 (silica gel, pentane/TBME, 2:1 + 4% triethylamine),

m.p. 75–81 °C. IR (KBr): ν = 3425 (s, NH), 3339 (s, NH), 3062 (m,

˜

CH_arom.), 2962 (vs, CH_aliph.), 2924 (vs, CH_aliph.), 2866 (s, CH_aliph.),

2856 (s, CH_aliph.), 1632 (vs, C=N), 1616 (s, C=C_arom.), 1589 (vs,

C=C_arom.), 1566 (vs), 1526 (s), 1479 (m), 1456 (s), 1389 (m), 1356

(m), 1321 (s), 1263 (m), 1227 (m), 1213 (m), 1166 (m), 1157 (m),

1109 (m), 1057 (m), 1026 (m), 960 (m), 925 (m), 802 (m), 773 (m),

696 (s) cm^–1. ¹H NMR (300 MHz, CDCl₃): δ = 0.79 [d, ³J = 6.2 Hz,

3

12 H, CH(CH₃)₂], 1.15 [s, 18 H, C(CH₃)₃], 3.51 (sept, J = 6.2 Hz,

8-tert-Butyl-9-isopropyl-2,4,6-triphenyl-1-oxa-3,5,7,9-tetraazanona-

tetra-1,3,5,7-tetraene (11b): From 0.45 g (4.00 mmol) of KOtBu,

0.98 g (4.00 mmol) of 1g and 1.10 g (4.00 mmol) of 10.^[14]

Recrystallization from triethylamine/ethyl acetate. Yield 0.63 g

2 H, CH), 4.07 (br., 1 H, NH), 7.26–7.30 (m, 3 H, CH_arom.), 7.60–

7.63 (m, 2 H, o-CH_arom.) ppm. ¹³C NMR (75.47 MHz, CDCl₃): δ

= 23.6 [CH(CH₃)₂], 29.0 [C(CH₃)₃], 38.8 [C(CH₃)₃], 46.2 [CH-

(CH₃)₂], 127.8, 128.1, 129.5 (C_arom.), 137.3 (i-C_arom.), 155.9 (C=N),

164.7 (C=N) ppm. MS (70 eV): m/z (%) = 370 (14) [M⁺], 313 (100)

[MH⁺–tBu–iPr], 271 (16) [iPrNCtBuNCPhNH₂⁺], 229 (52) [M⁺–

iPrNCtBuNH], 173 (12), 127 (61) [iPrNHCtBu⁺], 84 (64)

[iPrNCNH⁺], 57 (50) [tBu⁺]. HR MS: calcd. 371.3175; found

371.3151 [C₂₃H₃₈N₄+H⁺]. C₂₃H₃₈N₄(370.55): calcd. C 74.55 H

10.34 N 15.12; found C 72.47 H 10.49 N 14.67.

(1.38 mmol, 35%), yellow crystals, m.p. 171–172 °C. IR (KBr): ν =

˜

3312 cm^–1(s, NH), 3082 (m, CH_arom.), 3065 (m, CH_arom.), 3026 (m,

CH_arom.), 2978 (m, CH_aliph.), 2970 (m, CH_aliph.), 2932 (m, CH_aliph.),

2870 (m, CH_aliph.), 1647 (vs, C=O), 1626 (vs, C=N), 1601 (vs,

C=C_arom.), 1572 (vs, C=C_arom.), 1549 (vs, C=C_arom.), 1528 (vs),

1489 (s), 1450 (s), 1398 (s), 1369 (s), 1339 (s), 1315 (s), 1269 (s),

1211 (s), 1173 (s), 1134 (m), 1065 (m), 1042 (m), 1024 (m), 1018

(m), 893 (m), 806 (s), 777 (m), 704 (s), 694 (s) cm^–1. ¹H NMR

(300 MHz, CDCl₃): δ = 0.76 (d, ³J = 6.4 Hz, 6 H, CH(CH₃)₂), 1.00

[s, 9 H, C(CH₃)₃], 3.31 (br., 1 H, CH), 4.56 (br., 1 H, NH), 7.25–

7.50 (m, 9 H, CH_arom.), 7.70–7.73 (m, 2 H, o-CH_arom.), 7.91–7.94

(m, 2 H, o-CH_arom.), 8.50–8.10 (m, 2 H, o-CH_arom.) ppm. ¹³C NMR

(75.47 MHz, CDCl₃): δ = 22.8 [CH(CH₃)₂], 28.4 [C(CH₃)₃], 38.8

[C(CH₃)₃], 43.7 [CH(CH₃)₂], 127.9, 128.0, 128.3, 128.8, 129.4,

130.5, 130.6, 131.8 (C_arom.), 134.9 (i-C_arom.), 135.0 (i-C_arom.), 136.3

(i-C_arom.), 159.6 (C=N), 160.2 (C=N), 163.4 (C=N), 180.0 (C=O)

p p m . M S ( 7 0 e V ) : m/ z ( % ) = 4 5 2 ( 2 6 ) [ M ⁺] , 3 1 2 ( 2 0 )

[Ph₃C₃N₂OH⁺], 229 (13) [iPrNCtBuNCPh⁺], 180 (32) [PhCNPh⁺],

125 (21) [iPrNCtBu⁺–1], 105 (100) [PhCO⁺], 84 (36) [iPrNHCN⁺],

77 (24) [Ph⁺], 57 (39) [tBu⁺]. C₂₉H₃₂N₄O (452.57): calcd. C 76.96

H 7.13 N 12.38; found C 76.86 H 7.24 N 12.33.

General Procedure for the Reaction of 1 with N-Benzoylbenzimidoyl

Chloride (10): Potassium tert-butoxide (0.18 g, 1.60 mmol), dis-

solved in 7 mL of dry THF, was treated dropwise at 0 °C with 1

(1.60 mmol), dissolved in 15 mL of dry THF. After 5 min, the mix-

ture was warmed to room temperature and stirred for another

10 min. After cooling to 0 °C, the reaction mixture was treated

dropwise with N-benzoylbenzimidoyl chloride (10) (0.39 g,

1.60 mmol),^[14]dissolved in 5 mL of dry THF. After stirring at

room temperature for 1 d, the light yellow, slightly turbid reaction

mixture was diluted with 30 mL of dichloromethane and washed

with 30 mL of water. After separation of the layers, the aqueous

layer was extracted twice with dichloromethane. The combined or-

ganic layers were dried with magnesium sulfate, and the solvent

was removed in vacuo. The crude material was purified by column

chromatography (silica gel) or recrystallized.

X-ray Crystal Structure Analysis of 11b:^[21]Formula C₂₉H₃₂N₄O,

M = 452.59, yellow crystal 0.45×0.15×0.10 mm, a = 11.548(1), b

8-tert-Butyl-9-cyclopentyl-2,4,6-triphenyl-1-oxa-3,5,7,9-tetraaza-

nonatetra-1,3,5,7-ene (11a): From 0.43 g (3.80 mmol) of KOtBu,

1.03 g (3.80 mmol) of 1f and 0.93 g (3.80 mmol) 10.^[14]Column

chromatography (silica gel, eluent pentane/TBME, 2:1 + 4% trieth-

ylamine). Yield 0.62 g (1.60 mmol, 42%), colorless solid. R_f(DC) =

0.24 (silica gel, pentane/TBME, 2:1 + 4% triethylamine), m.p. 141 –

= 15.869(1), c = 28.183(1) Å, V = 5164.7(6) Å³, ρ_calcd.

=

1.164 g cm^–3, µ = 0.561 mm^–1, empirical absorption correction

(0.786 Յ T Յ 0.946), Z = 8, orthorhombic, space group Pbca (No.

61), λ = 1.54178 Å, T = 198 K, ω and φ scans, 7076 reflections

collected ( h, k, l), [(sinθ)/λ] = 0.59 Å^–1, 4142 independent (R_int

= 0.033) and 2290 observed reflections [I Ն 2σ(I)], 317 refined pa-

rameters, R = 0.059, wR₂= 0.187, max. residual electron density

0.29 (–0.21) e·Å^–3, hydrogen atom at N9 from difference Fourier

map, other calculated and refined as riding atoms.

143 °C IR (KBr): ν = 3335 (s, NH), 3082 (m, CH_arom.), 3061 (m,

˜

CH_arom.), 3026 (m, CH_arom.), 2966 (m, CH_aliph.), 2953 (m, CH_aliph.),

2872 (m, CH_aliph.), 1655 (C=O), 1643 (C=N), 1614 (vs, C=C_arom.),

1585 (vs, C=C_arom.), 1549 (vs, C=C_arom.), 1537 (vs, C=C_arom.), 1489

(m), 1448 (s), 1400 (m), 1348 (s), 1313 (s), 1258 (s), 1175 (8m), 1069

N-(1,2,4,6-Tetraphenyl-1,2-dihydro-1,3,5-triazin-2-yl)benzamide

(m), 1040 (m), 1026 (m), 1016 (m), 914 (m), 852 (m), 804 (m), 795 (12a): From 1a^[1,2](0.48 g, 1.6 mmol) and 10 (0.39 g, 1.6 mmol).^[14]

(m), 779 (m), 744 (m), 712 (m), 694 (s) cm^–1. H NMR (300 MHz, Column chromatography (silica gel, pentane/TBME, 2:1 + 5% tri-

1

CDCl₃): δ = 0.92–1.05 (m, 11 H, CH₃/CH₂), 1.29–1.52 (m, 6 H, ethylamine). Yield 0.36 g (0.71 mmol, 44%), colorless solid. R_f(DC)

Eur. J. Org. Chem. 2006, 3923–3937

www.eurjoc.org

3935

N. Heße, R. Fröhlich, B. Wibbeling, E.-U. Würthwein

FULL PAPER

= 0.20 (silica gel, pentane/TBME, 2:1 + 5% triethylamine), m.p.

recrystallized form triethylamine/ethyl acetate. Yield 0.14 g

173–177 °C. IR (KBr): ν = 3449 (m, NH), 3061 (m, CH_arom.), 3028

(0.30 mmol, 12%), light yellow solid, m.p. 166–168 °C. IR (KBr):

˜

(m, CH_arom.), 1684 (s, C=O), 1670 (m, C=N), 1614 (s), 1605 (m, ν = 3339 (s, NH), 3084 (m, CH_arom.), 3065 (m, CH_arom.), 3028 (m,

˜

C=C_arom.), 1574 (s, C=C_arom.), 1560 (m), 1522 (vs, C=C_arom.), 1489 CH_arom.), 2970 (s, CH_aliph.), 2934 (m, CH_aliph.), 2872 (m,

(vs), 1466 (vs), 1445 (s), 1394 (m), 1371 (m), 1337 (vs), 1269 (s), CH_aliph.),1641 (vs, C=O), 1595 (vs, C=N), 1582 (vs, C=C_arom.),

1258 (s), 1175 (m), 1136 (m), 1065 (m), 1030 (m), 768 (m), 737 (m)

1568 (vs, C=C_arom.), 1489 (vs, C=C_arom.), 1404 (s), 1377 (s), 1362

1

cm^–1. H NMR (600 MHz, CDCl₃): δ = 6.66 (br., 1 H, NH), 6.96 (s), 1317 (s), 1267 (vs), 1225 (s), 1173 (s), 1134 (m), 1101 (m), 1067

(br., 3 H, CH_arom.), 7.13–7.24 (m, 4 H, CH_arom.), 7.30–7.36 (m, 6

(m), 1055 (s), 1024 (s), 929 (m), 918 (m), 858 (m), 839 (s), 810 (m),

H, CH_arom.), 7.40–7.44 (m, 4 H, CH_arom.), 7.58–7.59 (m, 2 H, 775 (s), 723 (m), 706 (s), 692 (s) cm^–1

.

¹H NMR (600 MHz,

3

CH_arom.), 7.63–7.65 (m, 4 H, CH_arom.), 8.39–8.42 (m, 2 H, CH_arom.

)

[D₆]DMSO): δ = 0.40 [d, J = 6.6 Hz, 6 H, CH(CH₃)₂], 0.75 [s, 9

ppm. ¹³C NMR (150.84 MHz, CDCl₃): δ = 86.9 (C_quart.), 126.8, H, C(CH₃)₃], 2.92 (sept, ³J = 6.6 Hz, 1 H, CH), 4.37 (br., 1 H,

126.8, 127.3, 127.7, 127.9, 128.2, 128.4, 128.5, 128.6, 129.8, 130.5,

131.6 (C_arom.), 135.2 (i-C_arom.), 135.8 (i-C_arom.), 137.0 (i-C_arom.),

140.2 (i-C_arom.), 142.3 (i-C_arom.), 159.4 (C=N), 162.4 (C=N), 167.2

NH), 7.03–7.04 (m, 2 H, CH_arom.), 7.08–7.10 (m, 2 H, CH_arom.),

7.23–7.35 (m, 3 H, CH_arom.), 7.38–7.41 (m, 2 H, CH_arom.), 7.44–

7.50 (m, 4 H, CH_arom.), 7.54–7.56 (m, 1 H, CH_arom.), 7.76–7.77 (m,

(C=O) ppm. MS (70 eV): m/z (%) = 506 (4) [M⁺], 309 (56) 2 H, o-CH_arom.), 7.97–7.98 (m, 2 H, o-CH_arom.), 8.13–8.15 (m, 2 H,

[Ph₃C₃N₃⁺], 180 (32) [PhCNPh⁺], 121 (35) [PhCN₂H₄⁺], 105 (100) o-CH_arom.) ppm. ¹³C NMR (150.84 MHz, [D₆]DMSO): δ = 21.5

[PhCO⁺], 77 (69) [Ph⁺]. C₃₄H₂₆N₄O (506.58): calcd. C 80.61, H

5.17, N 11.06; found C 80.41, H 4.88, N 11.04.

[CH(CH₃)₂], 27.8 [C(CH₃)₃], 38.7 [C(CH₃)₃], 43.2 [CH(CH₃)₂],

127.5, 127.9, 128.1, 128.2, 128.2, 128.4, 128.6, 128.8, 130.4, 130.8,

131.5, 132.0 (C_arom.), 135.0, 135.2, 135.4 136.2 (i-C_arom.), 158.6

(C=N), 160.8 (C=N), 161.1 (C=N), 163.0 (C=N), 176.8 (C=O)

ppm. MS (70 eV): m/z (%) = 555 (5) [M⁺], 450 (9) [M⁺–PhCO],

3 0 9 ( 4 5 ) [ ( P h C N ) ₃⁺] , 2 7 4 ( 3 1 ) , 2 8 4 ( 2 2 ) , 2 3 0 ( 1 2 )

[ i P rNHC t BuNCPh ⁺] , 1 8 0 ( 1 6 ) [ P h N C P h ⁺] , 1 2 7 ( 2 2 )

[iPrNHCtBu⁺], 105 (100) [PhCO⁺], 103 (93) [PhCN⁺], 84 (43)

[iPrNHCN⁺], 77 (46) [Ph⁺], 57 (22) [tBu⁺]. C₃₆H₃₇N₅O (555.69):

calcd. C 77.81 H 6.71 N 12.60; found C 77.85 H 6.55 N 12.59.

X-ray Crystal Structure Analysis of 12a:^[21]Formula C₃₄H₂₆N₄O,

M = 506.59, colorless crystal 0.50×0.30×0.30 mm, a = 21.918(3),

b = 11.400(4), c = 24.069(5) Å, β = 115.75(1)°, V = 5417(2) Å³,

ρ_calcd.= 1.242 gcm^–3, µ = 0.601 mm^–1, empirical absorption correc-

tion (0.753 Յ T Յ 0.840), Z = 8, monoclinic, space group C2/c

(No. 15), λ = 1.54178 Å, T = 223 K, ω/2θ scans, 5677 reflections

collected ( h, +k, +l), [(sinθ)/λ] = 0.62 Å^–1, 5535 independent (R_int

= 0.023) and 4808 observed reflections [I Ն 2σ(I)], 356 refined pa-

rameters, R = 0.041, wR₂= 0.120, max. residual electron density

0.21 (–0.17) e·Å^–3, hydrogen atom at N7 from difference Fourier

map, other calculated and refined as riding atoms.

X-ray Crystal Structure Analysis of 14: Formula C₃₆H₃₇N₅O, M =

555.71, colorless crystal 0.30×0.05×0.03 mm, a = 15.432(1), b =

11.652(1), c = 17.553(1) Å, β = 96.77(1)°, V = 3134.3(4) Å³, ρ_calcd.

= 1.178 gcm^–3, µ = 0.565 mm^–1, empirical absorption correction

(0.849 Յ T Յ 0.983), Z = 4, monoclinic, space group P2₁/c (No.

45), λ = 1.54178 Å, T = 223 K, ω and φ scans, 18488 reflections

collected ( h, k, l), [(sinθ)/λ] = 0.54 Å^–1, 3983 independent (R_int

= 0.127) and 1987 observed reflections [I Ն 2σ(I)], 385 refined pa-

rameters, R = 0.126, wR₂= 0.412, max. residual electron density

0.29 (–0.27) e·Å^–3, hydrogen atom at N1 from difference Fourier

map, other calculated and refined as riding atoms, due to size and

quality of the crystals this analysis is of very poor quality and was

only done to confirm the connectivity and conformation of the

molecule.

N-(6-tert-Butyl-1,2,4-triphenyl-1,2-dihydro-1,3,5-triazin-2-yl)benz-

amide (12b): From 1d (0.84 g, 3.00 mmol), KOtBu (0.34 g,

3.00 mmol) and 10^[14](0.73 g, 3.00 mmol) following the procedure

for 12a. Column chromatography (silica gel, pentane/TBME, 2:1 +

5% triethylamine) did not lead to completely pure product. Yield

0.27 mg (0.60 mmol, 18%), colorless solid. R_f(DC) = 0.21 (silica

gel, pentane/TBME, 5:1 + 1% triethylamine), m.p. 96–101 °C. IR

(KBr): ν = 3312 (m, NH), 3061 (m, CH_arom.), 3034 (m, CH_arom.),

˜

2966 (m, CH_aliph.), 2870 (m, CH_aliph.), 1734 (m, C=O), 1661 (vs,

C=N), 1597 (s, C=C_arom.), 1518 (vs, C=C_arom.), 1491 (s), 1439 (s),

1394 (m), 1366 (s), 1319 (s), 1273 (m), 1242 (m), 1171 (m), 1074

(w), 1030 (m), 929 (w), 905 (w), 754 (m), 717 (m), 698 (s) cm^–1. ¹H

NMR (300 MHz, CDCl₃): δ = 1.31 (s, 9 H, CH₃), 7.08–7.66 (m,

CH_arom.), 8.35–8.36 (m, o-CH_arom.) ppm. ¹³C NMR (75.47 MHz,

CDCl₃): δ = 27.6 (CH₃), 39.5 [C(CH₃)₃], 87.7 (C_quart.), 126.8–131.7

(C_arom.), 135.1 (i-C_arom.), 136.6 (i-C_arom.), 137.7 (i-C_arom.), 160.7

(C=N), 166.6 (C=O), 176.5 (C=N) ppm. MS (70 eV): m/z (%) =

486 (4) [M⁺], 429 (13) [M⁺–tBu], 180 (69) [PhCNPh⁺], 105 (100)

[PhCO⁺], 77 (46) [Ph⁺].

Acknowledgments

The authors thank the Deutsche Forschungsgemeinschaft (Sonde-

rforschungsbereich 424) and the Fonds der Chemischen Industrie

(Frankfurt) for financial support.

[1] N. Heße, R. Fröhlich, I. Humelnicu, E.-U. Würthwein, Eur. J.

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10-tert-Butyl-11-isopropyl-2,4,6,8-tetraphenyl-1-oxa-3,5,7,9,11-

pentaazaundeca-1,3,5,7,9-pentaene (14): Under argon, KOtBu

(0.22 g, 2.00 mmol), dissolved in 10 mL of dry THF, was treated

dropwise at 0 °C with 1g (0.49 g, 2.00 mmol), dissolved in 10 mL

of THF. After stirring at 0 °C for 5 min and at room temperature

for another 10 min, 2,4,6-triphenyl-1,3,5-oxadiazinium pentachlo-

rostannate (13)^[26](1.21 g, 2.00 mmol) was added. Within a few

minutes of stirring at 0 °C, the yellow solid dissolved, yielding a

yellow, slightly turbid reaction mixture. After stirring at 0 °C for

1 h, stirring was continued at room temperature for another 1 h.

Then the reaction mixture was poured into 20 mL of a 2  sodium

hydroxide solution. After three extractions with dichloromethane,

the combined organic extracts were dried with magnesium sulfate.

The solvent was removed in vacuo and the crude product was

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www.eurjoc.org

Eur. J. Org. Chem. 2006, 3923–3937

Triazapentadienes as Building Blocks for Dihydrotriazines and Oligonitriles

FULL PAPER

J. W. Ochterski, P. Y. Ayala, K. Morokuma, G. A. Voth, P. Sal-

vador, J. J. Dannenberg, V. G. Zakrzewski, S. Dapprich, A. D.

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boul, S. Clifford, J. Cioslowski, B. B. Stefanov, G. Liu, A. Lia-

shenko, P. Piskorz, I. Komaromi, R. L. Martin, D. J. Fox, T.

Keith, M. A. Al-Laham, C. Y. Peng, A. Nanayakkara, M.

Challacombe, P. M. W. Gill, B. Johnson, W. Chen, M. W.

Wong, C. Gonzalez, J. A. Pople, Gaussian 03, Revision C.01,

Gaussian, Inc., Wallingford, CT, 2004. Details of the quantum-

chemical calculations may be obtained from E.-U. W. upon re-

quest.

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[21] Data sets were collected with Enraf–Nonius CAD4 and Nonius

KappaCCD diffractometers, in case of Mo radiation equipped

with a rotating anode generator. Programs used: data collection

EXPRESS (B. V. Nonius, 1994) and COLLECT (B. V. Nonius,

1998), data reduction MolEN (K. Fair, B. V. Enraf–Nonius,

1990) and Denzo-SMN (Z. Otwinowski, W. Minor, Methods

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data SORTAV (R. H. Blessing, Acta Crystallogr., Sect. A 1995,

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426), and Denzo (Z. Otwinowski, D. Borek, W. Majewski, W.

Minor, Acta Crystallogr., Sect. A 2003, 59, 228–234), structure

solution SHELXS-97 (G. M. Sheldrick, Acta Crystallogr., Sect.

A 1990, 46, 467–473); structure refinement SHELXL-97 (G. M.

Sheldrick, University of Göttingen, 1997), graphics

SCHAKAL (E. Keller, 1997). CCDC-298795 (1b), -298797

(1e), -298801 (3a), -298803 (6a), -298804 (6b), -298796 (8a), -

298798 (9a), -600789 (9b), -298799 (11a), -298800 (11b), -

298802 (12a) and -600788 (14) contain the supplementary crys-

tallographic data for this paper. These data can be obtained

free of charge from The Cambridge Crystallographic Data

Centre via www.ccdc.cam.ac.uk/data_request/cif.

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Received: April 24, 2006

Published Online: July 3, 2006

Eur. J. Org. Chem. 2006, 3923–3937

www.eurjoc.org

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1,3,5-Triazapenta-1,3-dienes: Useful building blocks for the synthesis of 1,2-dihydro-1,3,5-triazines and oligonitriles

DOI: 10.1002/ejoc.200600352

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