A straightforward and mild method of tethering monosaccharides to thieno[2,3-d]pyrimidinones via the copper(I)-catalyzed azide-alkyne 'click chemistry'

Article abstract of DOI:10.5560/ZNB.2012-0193

A mild and versatile method based on Cu(I)-catalyzed [3+2] cycloaddition (Meldal-Sharpless reaction) was developed to tether biomolecules, such as monosacharides or lipophylic azides, to alkyne functions of spirobenzo[b] thieno[2,3-d]pyrimidine-10-cyclohe

Full text of DOI:10.5560/ZNB.2012-0193

A Straightforward and Mild Method of Tethering Monosaccharides to
Thieno[2,3-d]pyrimidinones via the Copper(I)-catalyzed Azide-Alkyne
‘Click Chemistry’
Essam Kh. Ahmed and Mohamed A. Ameen
Chemistry Department, Faculty of Science, El Minia University, El Minia 61511, Egypt
Reprint requests to Mohamed A. Ameen. E-mail: m ameen10@yahoo.com
Z. Naturforsch. 2012, 67b, 1282 – 1288 / DOI: 10.5560/ZNB.2012-0193
Received July 8, 2012
A mild and versatile method based on Cu(I)-catalyzed [3+2] cycloaddition (Meldal-Sharpless re-
action) was developed to tether biomolecules, such as monosacharides or lipophylic azides, to alkyne
functions of spirobenzo[b]thieno[2,3-d]pyrimidine-10-cyclohexane. The reactions are highlighted by
their modularity and high efficiency with excellent yields in most cases. The products are interesting
precursors for a variety of applications.
Key words: Thienopyrimidinone, Alkynes, Azides, Click Chemistry
Introduction
organic compounds and the stability of these groups to-
ward other reaction conditions. The copper-catalyzed
The construction of structures of increasing size and (CuAAC) version has proven to be popular in applica-
often corresponding complexity from modular compo- tions ranging from drug discovery [10] to surface sci-
nents not only lies at the heart of synthetic chemistry, ence [11], where rapid and reliable bond formation is
but is also the basis of many biological processes es- required. The significant growth of ‘click chemistry’
sential to life [1 – 4]. An excellent example of this is the and in particular the copper-catalyzed azide-alkyne cy-
‘click chemistry’ which represents a modular approach cloaddition reaction [12, 13] (CuAAC) in the fields
toward syntheses and use only the most practical chem- of macromolecular and surface science highlights the
ical transformations to make molecular connections fundamental necessity for a core group of reproducible
with excellent fidelity [5 – 7]. The 1,3-dipolar cycload- and broadly applicable reactions which may be em-
dition of azides and alkynes (AAC) to give substituted ployed across diverse disciplines of the physical and
1,2,3-triazoles has emerged as a powerful linking re- biological sciences. Among promising targeting ther-
action in both uncatalyzed [8] and metal-catalyzed [9] apies for cancer treatment, substituted thienopyrimi-
forms (Fig. 1).
dones have continued to retain attention of both aca-
The practical importance of the process derives from demic institutions and pharmaceutical companies in
the easy introduction of azide and alkyne functions into the last few years [14 – 16]. To the best of our knowl-
edge thieno[2,3-d]pyrimidinones have never been con-
jugated with saccharides using a click reaction. Only
very recently we became interested in the application
of the copper-catalyzed cycloaddition of azides and
alkynes to pyridothienopyrimidinone [11, 17] systems
in order to tether carbohydrates and amino acids to this
pharmacophor via 1,2,3-triazole linkers for novel anti-
cancer therapeutics or nanoscaled molecular rods.
As an extension of this work we now report the
preparation of novel spirothienopyrimidinones which
Fig. 1. 1,3-Dipolar cycloaddition of azides and alkynes
(AAC).
© 2012 Verlag der Zeitschrift fu¨r Naturforschung, Tu¨bingen · http://znaturforsch.com
Unauthenticated
Download Date | 3/17/17 3:20 PM

E. Kh. Ahmed – M. A. Ameen · Tethering Monosaccharides to Thieno[2,3-d]pyrimidinones
1283
have the advantage of introducing multiple biological for HCC-CH2) with absence of a C=S signal which ap-
functionalities via conjugation with biomolecules us- peared at δ = 174.0 ppm in compound 4c. In addition
ing ‘click chemistry’.
the 1H NMR spectrum of 5 showed a broad singlet and
doublet at δ = 2.18 and 3.96 ppm for the CH and CH2
units of the propargyl group, respectively.
Results and Discussion
Making use of the alkyne function in compound
The synthesis of 3-substituted-2-thioxo-4-oxo-3, 5 we seeked to tether different monosaccharides via
4,5,8-tetrahydro-spirobenzo[b]thieno[2,3-d]pyrimidi- 1,2,3-triazoles. Under the broadly known copper-
ne-7(6H),10-cyclohexane (4a – c) to construct the catalyzed alkyne/azide click (CuAAC) reaction con-
target S-propargylated pyrimidinone 5 is summarized ditions, reacting compound 5 with 1-azido-1-deoxy-
in Scheme 1. At first, the reaction of the readily 2,3,4,6-tetraacetyl-β-D-hexoses (glucose and galac-
available spiro[5,5]undecane-3-one [18 – 21] with tose) using CH3OH-H2O (1:1) as a solvent mixture
ethyl cyanoacetate and sulfur in absolute ethanol and produced the cycloaddition products 6a,b in excellent
morpholine, in analogy to Gewald [22] procedures, yields (Scheme 2). Based on these results we applied
gave the 2-amino-4,7-dihydro-spiro[benzo[b]thio- a similar methodology to produce the octadecyl-1,2,3-
phene-6(5H),10-cyclohexane]-3-carboxylic acid ethyl triazolo product 6c by reacting the alkyne 5 with octa-
ester 1, which was converted into the isothiocyanate decyl azide.
product 2 by treatment with thiophosgene. The key
The 1,2,3-triazole-bearing thienopyrimidinone con-
intermediates 3a – c could be obtained by treatment jugates 6a – c appeared as colorless, stable solids. Their
of the isothiocyanate 2 with hydrazine hydrate, ethyl structures were confirmed by spectroscopic methods.
carbazate or glycine ethyl ester hydrochloride in the In addition to the signals of the thienopyrimidinone,
presence of triethylamine with a good yield. Base- the biomolecules, and the linker moieties, diagnostic
catalyzed cyclization of compounds 3a – c followed signals for the 1,2,3-triazole ring were found in the
by reprotonation of the obtained sodium salt by HCl NMR spectra [δ = 7.7 – 7.8 (1H NMR), δ = 120 – 122
produced the thione precursors 4a – c in excellent and 142 – 146 ppm (13C NMR)].
yields.
Propargylation of the SH group in compound 4c
with propargyl bromide in the presence of diisopropyl-
ethylamine gave rise to the product 5 (Scheme 2). The
position of the propargyl group in 5 was elucidated by
13C NMR spectroscopy (δ = 54.2, 72.2 and 77.7 ppm
Scheme 1. Synthesis of the pyrimidinone derivatives 4a – c.
Scheme 2. Synthesis of the clicked products 6a – c.
Unauthenticated
Download Date | 3/17/17 3:20 PM

1284
E. Kh. Ahmed – M. A. Ameen · Tethering Monosaccharides to Thieno[2,3-d]pyrimidinones
in an unusual conversion. All products obtained were
hitherto unknown.
Experimental Section
General Remarks: All reactions were carried out with
oven-dried glassware. Solvents were dried. Starting mate-
rials were purchased from Aldrich and Merck. Azides of
monosaccharides and octadecanyl azide were synthesized ac-
cording to literature procedures [28, 29]. TLC analysis was
performed on Merck silica gel 60 F254 plates and visu-
alized by UV illumination and by charring with phospho-
molybdic acid, potassium permanganate or ninhydrin. Sil-
ica gel 60 (0.035 – 0.070 mm, Acros) was used for prepar-
ative column chromatography. Melting points were deter-
mined on a Boetius hotstage apparatus and are uncorrected.
1H NMR and 13C NMR spectra were recorded at 300 and
75.5 MHz, respectively, on a Bruker AC-300 with TMS as
Scheme 3. Synthesis of the disulfide product 8.
internal standard. High-resolution mass spectra (ESI) were
measured with a Thermo Finnigan LTQ-FT-ICR-MS with
MeOH as solvent.
Although homodisulfides are generally synthesized
via oxidative coupling of their corresponding thi-
ols [23], many procedures are offered for this conver-
sion including using halogen-containing reagents [24],
metal ions [25] and hydrogen peroxide [26]. Suc-
holeiki [27] reported that thioethers can readily be
used for the attachment of organic molecules to solid
supports and can undergo light-induced heterogeneous
C–S bond cleavage upon irradiation with 350 nm
light.
Remarkably, removal of the acetyl groups from the
sugar units of 6a to produce compound 7 turned out to
be difficult in the presence of unstoichiometric amount
of sodium methoxide (0.1 equiv.). Only a mixture of
products was obtained under these conditions contain-
ing traces of the product. The reaction was repeated
with 0.3 equiv. of sodium ethoxide to avoid transesteri-
fication. UPLC analysis revealed that only the disulfide
product 8 was isolated as a solid which was character-
ized by HRMS and NMR spectroscopy (Scheme 3).
Synthesis of 2-isothiocyanato-4,7-dihydrospiro[benzo[b]-
thiophene-6(5H),10-cyclohexane]-3-carboxylic acid ethyl
ester (2)
A suspension of compound 1 (0.60 g, 2 mmol) in CH2Cl2
(5 mL) was added to a stirred suspension of calcium carbon-
ate (1.8 g, 18 mmol) in water (10 mL) and CH2Cl2 (20 mL)
at room temperature. To the stirred mixture, thiophosgene
(0.24 g, 2 mmol) was added slowly in an ice bath. The
temperature of the reaction mixture was allowed to reach
room temperature. Stirring was continued over night. In-
organic salts were removed by filtration, and then the or-
ganic phase was washed with water (2 × 20 mL), 5% aque-
ous sodium bicarbonate (2 × 20 mL) and brine (30 mL). Af-
ter drying over magnesium sulfate, the solvent was removed
under vacuum, and the residue was purified by column
chromatography to give yellow crystals (0.42 g, 73%); m.
p. 124 – 125 ◦C. – Rf = 0.65 (CH2Cl2,100%). – 1H NMR
(300 MHz, CDCl3): δ = 1.29 (t, 4H, J = 3.3 Hz, H-20, 60),
1.34 (t, 3H, J = 7.1 Hz, COOCH2CH3), 1.37 – 146 (m, 6H,
H-30,40,50), 1.56 (t, 2H, J = 6.5 Hz, H-5), 2.39 (s, 2H, H-
7), 2.69 (t, 2H, J = 6.5 Hz, H-4), 4.29 (q, 2H, J = 7.2 Hz,
COOCH2CH3). – 13C NMR (75 MHz, CDCl3): δ = 14.5
(CH3), 21.8 (C-30,50), 23.0 (C-4), 26.6 (C-40), 32.5 (C-5),
32.7 (Cq), 35.9 (C-20,60), 36.1 (C-7), 60.8 (CH2, ester), 126.3
(C-7a), 131.4 (C-3a), 132.7 (C=S), 133.8 (C-3), 137.3 (C-2),
162.1 (C=O, ester). – HRMS (ESI): m/z = 336.1062 (calcd.
336.1092 for C17H22NO2S2, [M+H]+).
Conclusion
In the present context, the copper-catalyzed 1,3-
dipolar cycloaddition (CLICK) reaction was shown to
be an ideal choice as it usually proceeds in high yield
under mild conditions. We adopted a convergent strat-
egy, in which a preformed alkyne core functionalized
with the desired thieno[2,3-d]pyrimidinone could be
conjugated with saccharides and a lipophilic azide.
Synthesis of 3a – c
To a solution of the isothiocyanate 2 (2 mmol) in
A novel heterocyclic disulfide system was obtained dichloromethane (5 mL), a solution of amine (2 mmol) in
Unauthenticated
Download Date | 3/17/17 3:20 PM

E. Kh. Ahmed – M. A. Ameen · Tethering Monosaccharides to Thieno[2,3-d]pyrimidinones
1285
dichloromethane (5 mL) and triethylamine (0.30 g, 3 mmol) J = 6.8 Hz, NHCH2COOCH2CH3), 4.30 (q, 2H, J = 7.2 Hz,
were added with stirring. The mixture was stirred for 1 – 2 h, COOCH2CH3), 4.41 (s, 2H, NHCH2), 10.18 (bs, H, NH),
and then the solvent was removed under reduced pressure 12.54 (bs, 1H, NH). – 13C NMR (75 MHz, CDCl3): δ = 14.3
yielding compounds 3a – c.
(CH3), 14.5 (CH3), 21.3 (C-30,50), 22.8 (C-4), 26.2 (C-40),
32.1 (C-5), 32.6 (Cq), 34.5 (C-20,60), 35.4 (C-7), 47.9 (CH2),
60.9 (CH2, ester), 61.4 (CH2, ester), 111.8 (C-7a), 124.9
(C-3a), 129.0 (C-3), 148.6 (C-2), 155.7 (C=O, ester), 165.3
(C=O, ester), 176.7 (C=S). – HRMS (ESI): m/z = 439.1633
(calcd. 439.1725 for C21H31N2O4S2, [M+H]+).
2-[Hydrazinocarbothioyl]amino-4,7-dihydro-
spiro[benzo[b]thiophene-6(5H),10-cyclohexane]-3-
carboxylic acid ethyl ester (3a)
The product was obtained, following the general proce-
dure under stirring at r. t. for 1 h, as a colorless solid product
(0.57 g, 91%); m. p. 198 – 199 ◦C. – 1H NMR (300 MHz,
DMSO): δ = 1.29 – 1.43 (m, 13H, H-20, 60, COOCH2CH3,
H-30,40,50), 1.56 (t, 2H, J = 6.5 Hz, H-5), 2.41 (s, 2H, H-
7), 2.69 (t, 2H, J = 6.5 Hz, H-4), 4.29 (q, 2H, J = 7.2 Hz,
COOCH2CH3), 4.98 (bs, 1H, NHNH2), 7.16 (bs, 2H, NH2),
9.64 (bs, 1H, NH). – 13C NMR (75 MHz, DMSO): δ = 14.2
(CH3), 21.3 (C-30,50), 22.8 (C-4), 26.2 (C-40), 32.1 (C-5),
32.7 (Cq), 34.6 (C-20,60), 35.1 (C-7), 60.0 (CH2, ester), 111.0
(C-7a), 124.2 (C-3a), 128.8 (C-3), 149.3 (C-2), 165.0 (C=O,
ester), 176.8 (C=S). – HRMS (ESI): m/z = 368.1463 (calcd.
368.1466 for C17H26N3O2S2, [M+H]+).
Synthesis of 4a – c
A sodium ethoxide solution (0.05 g, 2 mmol in 10 mL of
abs. ethanol) was added to the crude corresponding com-
pound 3 (2 mmol). The reaction mixture was stirred at r. t.
over night. The formed sodium salt was collected, dissolved
in water and the pH of the solution adjusted with hydrochlo-
ric acid to pH = 4. The solid product was filtered off, washed
with water and recrystallized from ethanol to give com-
pounds 4a – c.
3-Amino-2-thioxo-4-oxo-1,2,3,4,5,8-hexahydro-
spirobenzo[b]thieno[2,3-d]pyrimidine-7(6H),10-
cyclohexane (4a)
2-[(Ethoxycarbonyl)-aminocarbothioyl]amino-4,7-dihydro-
spiro[benzo[b]thiophene-6(5H),10-cyclohexane]-3-
carboxylic acid ethyl ester (3b)
The product was obtained, following the general proce-
dure, as colorless crystals from methanol (0.54 g, 84%);
m. p. 200 – 201 ◦C. – 1H NMR (300 MHz, DMSO):
δ = 1.29 – 141 (m, 10H, H-20,30,40,50,60), 1.57 (t, 2H,
J = 6.4 Hz, H-6), 2.46 (s, 2H, H-8), 2.75 (t, 2H, J = 6.1 Hz,
H-5), 6.29 (bs, 2H, NH2), 13.86 (bs, 1H, NH). – 13C NMR
(75 MHz, DMSO): δ = 21.2 (C-30,50), 21.6 (C-5), 26.1 (C-
40), 31.8 (C-6), 32.8 (Cq), 34.8 (C-8), 35.3 (C-20,60), 114.6
(C-4b), 127.9 (C-4a), 129.1 (C-8a), 147.4 (C-9a), 152.8
(C=O), 166.3 (C=S). – HRMS (ESI): m/z = 322.1023 (calcd.
322.1048 for C15H20N3OS2, [M+H]+).
The product was obtained, following the general pro-
cedure under stirring at r. t. for 1 h as colorless solid
product (0.78 g, 89%); m. p. 110 ◦C (decomposed). – 1H
NMR (300 MHz, DMSO): δ = 1.23 – 1.42 (m, 16H, H-20,
60, 2COOCH2CH3, H-30,40,50), 1.57 (t, 2H, J = 6.5 Hz, H-
5), 2.44 (s, 2H, H-7), 2.70 (t, 2H, J = 6.5 Hz, H-4), 4.16 (q,
2H, J = 6.8 Hz, NHCOOCH2CH3), 4.30 (q, 2H, J = 7.2 Hz,
COOCH2CH3), 9.77 (bs, 1H, NHNH), 10.24 (bs, H,
NHNH), 12.38 (bs, 1H, NH). – 13C NMR (75 MHz, DMSO):
δ = 14.3 (CH3), 14.6 (CH3), 21.3 (C-30,50), 22.7 (C-4), 26.2
(C-40), 32.2 (C-5), 32.6 (Cq), 34.6 (C-20,60), 35.3 (C-7), 60.5
(CH2, ester), 61.3 (CH2, ester), 111.8 (C-7a), 125.0 (C-3a),
129.0 (C-3), 148.8 (C-2), 155.8 (C=O, ester), 165.8 (C=O,
ester), 177.1 (C=S). – HRMS (ESI): m/z = 440.1663 (calcd.
440.1778 for C20H30N3O4S2, [M+H]+).
3-(Ethoxycarbonyl)amino-2-thioxo-4-oxo-1,2,3,4,5,8-
hexahydro-spirobenzo[b]thieno[2,3-d]-pyrimidine-
7(6H),10-cyclohexane (4b)
The product was obtained, following the general proce-
dure, as colorless crystals from methanol (0.61 g, 79%); m.
p. 132 – 133 ◦C. – 1H NMR (300 MHz, DMSO): δ = 1.26
(t, 3H, J = 7.1 Hz, COOCH2CH3), 1.32 – 143 (m, 10H, H-
20,30,40,50,60), 1.59 (t, 2H, J = 6.4 Hz, H-6), 2.49 (s, 2H, H-
8), 2.72 (t, 2H, J = 6.1 Hz, H-5), 4.14 (q, 2H, J = 7.1 Hz,
COOCH2CH3), 10.16 (bs, 1H, NH), 13.71 (bs, 1H, NH).
2-[(2-Ethoxy-2-oxoethyl)-aminocarbothioyl]amino-4,7-
dihydro-spiro[benzo[b]thiophene-6(5H),10-cyclohexane]-3-
carboxylic acid ethyl ester (3c)
The product was obtained, following the general pro-
–
13C NMR (75 MHz, DMSO): δ = 14.5 (CH3), 21.2 (C-
cedure under stirring at r. t. for 2 h as a colorless solid 30,50), 21.6 (C-5), 26.1 (C-40), 31.7 (C-6), 32.5 (Cq), 35.2
product (0.79 g, 90%); m. p. 139 – 140 ◦C. – 1H NMR (C-8), 35.5 (C-20,60), 61.1 (CH2, ester), 115.3 (C-4b), 128.4
(300 MHz, CDCl3): δ = 1.27 – 1.41 (m, 16H, H-20, 60, (C-4a), 129.9 (C-8a), 147.4 (C-9a), 152.8 (C=O), 166.3
2COOCH2CH3, H-30,40,50), 1.56 (t, 2H, J = 6.5 Hz, H-5), (C=S). – HRMS (ESI): m/z = 394.1230 (calcd. 394.1259 for
2.45 (s, 2H, H-7), 2.68 (t, 2H, J = 6.5 Hz, H-4), 4.16 (q, 2H, C18H24N3O3S2, [M+H]+).
Unauthenticated
Download Date | 3/17/17 3:20 PM

1286
E. Kh. Ahmed – M. A. Ameen · Tethering Monosaccharides to Thieno[2,3-d]pyrimidinones
3-(2-Ethoxy-2-oxoethyl)-2-thioxo-4-oxo-1,2,3,4,5,8-
hexahydro-spirobenzo[b]thieno[2,3-d]-pyrimidine-
7(6H),10-cyclohexane (4c)
luted with H2O and extracted with CH2Cl2 (3 × 15 mL). The
combined organic layers were dried (Na2SO4), filtered and
concentrated. Column chromatography purification gave the
products 6a–c.
The product was obtained, following the general proce-
dure, as colorless crystals from methanol (0.63 g, 81%); m.
p. 189 – 190 ◦C. – 1H NMR (300 MHz, CDCl3): δ = 1.25
(t, 3H, J = 7.1 Hz, COOCH2CH3), 1.29 – 137 (m, 10H, H-
20,30,40,50,60), 1.57 (t, 2H, J = 6.2 Hz, H-6), 2.39 (s, 2H, H-
8), 2.78 (t, 2H, J = 6.2 Hz, H-5), 4.22 (q, 2H, J = 7.1 Hz,
COOCH2CH3), 5.17 (s, 2H, N-CH2), 11.95 (bs, 1H, NH).
3-(2-Ethoxy-2-oxoethyl)-2-[(1-(2,3,4,6-tetra-o-acetyl-β-d-
glucopyranosyl)-1H-1,2,3-triazol-4-yl)methyl]sulfanyl-4-
oxo-3,4,5,8-tetrahydro-spirobenzo[b]thieno[2,3-d]-
pyrimidine-7(6H),10-cyclohexane (6a)
The product was obtained, following the general pro-
cedure under stirring at r. t. for 16 h as colorless crystals
(0.73 g, 91%); m. p. 180 – 181 ◦C. – Rf = 0.34 (CH2Cl2-
CH3OH, 98:2). – 1H NMR (300 MHz, CDCl3): δ = 1.22
(t, 3H, J = 7.1 Hz, COOCH2CH3), 1.33 – 144 (m, 10H, H-
20,30,40,50,60), 1.62 (t, 2H, J = 6.4 Hz, H-6), 1.76 (s, 3H,
COCH3), 1.95 (s, 3H, COCH3), 1.98 (s, 3H, COCH3), 1.99
(s, 3H, COCH3), 2.52 (s, 2H, H-8), 2.88 (t, 2H, J = 6.1 Hz,
H-5), 3.90 – 4.21 (m, 5H, COOCH2CH3, C5H-CH2-OCO,
C5H-CH2-OCO), 4.47 – 4.53 (br, 2H, CH2-Ctriazole), 4.76
(s, 2H, N-CH2), 5.18 (m, 1H, C3H), 5.33 (m, 2H, C2H,
C4H ), 5.76 (d, 1H, J = 6.4 Hz, C1H-Ntriazole), 7.78 (s,
1H, CHar−triazole). – 13C NMR (75 MHz, CDCl3): δ = 14.1
(CH3), 20.1, 20.5, 20.6, 20.7 (4COCH3), 21.8 (C-30,50),
22.2 (C-5), 26.6 (C-40), 27.1 (CH2-C), 32.4 (C-6), 32.9
(Cq), 36.0 (C-20,60), 36.4 (C-8), 44.5 (N-CH2), 61.5 (C5H-
CH2-OCO), 62.0 (CH2, ester), 67.7 (C4H), 70.2 (C2H),
72.6 (C3H), 75.2 (C5H), 85.9 (C1H-Ntriazole), 118.6 (C-
4a), 121.6 (CHar−triazole), 130.5 (C-8a), 131.5 (C-4b), 142.2
(Cq−triazole), 154.6 (C-9a), 158.0 (C=O), 162.0 (C=O, es-
ter), 166.9 (C-2), 168.7, 169.4, 169.9, 170.5 (4COCH3).
– HRMS (ESI): m/z = 804.2420 (calcd. 804.2584 for
C36H46N5O12S2, [M+H]+).
–
13C NMR (75 MHz, CDCl3): δ = 14.2 (CH3), 21.8 (C-
30,50), 22.0 (C-5), 26.5 (C-40), 32.1 (C-6), 33.1 (Cq), 35.8,
35.9 (C-20,60), 36.1 (C-8), 47.3 (N-CH2), 61.9 (CH2, es-
ter), 116.5 (C-4b), 128.8 (C-4a), 131.2 (C-8a), 148.9 (C-9a),
154.4 (C=O), 154.9 (C=O, ester), 174.6 (C=S). – HRMS
(ESI): m/z = 393.1333 (calcd. 393.1307 for C19H25N2O3S2,
[M+H]+).
Synthesis of 3-(2-ethoxy-2-oxoethyl)-2-propargylsulfanyl-4-
oxo-3,4,5,8-tetrahydro-spiro-benzo[b]thieno[2,3-d]-
pyrimidine-7(6H),10-cyclohexane (5)
Propargyl bromide (1.10 g, 9 mmol) was added to a sus-
pension of compound 4c (1.18 g, 3 mmol) and iPr2NEt
(0.70 g, 6 mmol) in DMF (15 mL) and the resulting mix-
ture was stirred at room temperature for 6 h. The solution
was evaporated to dryness in vacuo. The residue was diluted
with water and then extracted with CH2Cl2 (3 × 30 mL).
The combined organic extracts were dried over anhydrous
Na2SO4, filtered and the solvents evaporated under reduced
pressure. The obtained product was purified by column chro-
matography. Yield: 0.91 g (71%); m. p. 112 – 113 ◦C. –
Rf = 0.65 (CH2Cl2, 100%). – 1H NMR (300 MHz, CDCl3):
δ = 1.24 (t, 3H, J = 7.1 Hz, COOCH2CH3), 1.31 – 140 (m,
10H, H-20,30,40,50,60), 1.60 (t, 2H, J = 6.2 Hz, H-6), 2.18 (bs,
1H, C-CH), 2.50 (s, 2H, H-8), 2.86 (t, 2H, J = 5.8 Hz, H-
5), 3.96 (d, 2H, J = 2.4 Hz, CH2-C), 4.20 (q, 2H, J = 7.1 Hz,
COOCH2CH3), 4.76 (s, 2H, N-CH2). – 13C NMR (75 MHz,
CDCl3): δ = 14.1 (CH3), 21.3, 21.8 (C-30,50), 22.2 (C-5),
26.6 (C-40), 32.5 (C-6), 32.9 (Cq), 36.0 (C-20,60), 36.3 (C-
8), 44.5 (N-CH2), 54.2 (CH2-C), 62.1 (CH2, ester), 72.2 (C-
CH), 77.7 (C-CH), 118.5 (C-4a), 130.3 (C-8a), 131.7 (C-
4b), 153.7 (C-9a), 157.9 (C=O), 162.0 (C=O, ester), 166.8
(C-2). – HRMS (ESI): m/z = 431.1476 (calcd. 431.1463 for
C22H27N2O3S2, [M+H]+).
3-(2-Ethoxy-2-oxoethyl)-2-[(1-(2,3,4,6-tetra-o-acetyl-β-d-
galactopyranosyl)-1H-1,2,3-triazol-4-yl)methyl]sulfanyl-4-
oxo-3,4,5,8-tetrahydro-spirobenzo[b]thieno[2,3-d]-
pyrimidine-7(6H),10-cyclohexane (6b)
The product was obtained, following the general pro-
cedure, under stirring at r. t. for 12 h as colorless crys-
tals (0.75 g, 94%); m. p. 92 – 93 ◦C. – Rf = 0.39 (CH2Cl2-
CH3OH, 98:2). – 1H NMR (300 MHz, CDCl3): δ = 1.23
(t, 3H, J = 7.1 Hz, COOCH2CH3), 1.33 – 144 (m, 10H, H-
20,30,40,50,60), 1.62 (t, 2H, J = 6.3 Hz, H-6), 1.78 (s, 3H,
COCH3), 1.94 (s, 3H, COCH3), 1.96 (s, 3H, COCH3), 2.13
(s, 3H, COCH3), 2.50 (s, 2H, H-8), 2.88 (t, 2H, J = 5.9 Hz,
H-5), 4.19 (m, 5H, COOCH2CH3, C5H-CH2-OCO, C5H-
CH2-OCO), 4.44 – 4.58 (m, 2H, CH2-Ctriazole), 4.76 (s, 2H,
Synthesis of 6a – c
The azido compound (1.0 mmol) was added to the alkyne N-CH2), 5.17 (dd, 1H, J1 = 3.3 Hz, J2 = 10.3 Hz, C3H),
substrate 5 (1.0 mmol) in CH3OH-H2O (1:1) (25 mL). Then 5.47 (m, 2H, C2H, C4H ), 5.73 (d, 1H, J = 9.2 Hz, C1H-
sodium ascorbate (0.4 mmol) and CuSO4·5H2O (0.2 mmol) Ntriazole), 7.79 (s, 1H, CHar−triazole). – 13C NMR (75 MHz,
were added. The mixture was stirred at room temperature CDCl3): δ = 14.1 (CH3), 20.2, 20.5, 20.6, 20.7 (4COCH3),
for the specified time. The mixture was concentrated, di- 21.8 (C-30,50), 22.2 (C-5), 26.6 (C-40), 27.2 (CH2-C),
Unauthenticated
Download Date | 3/17/17 3:20 PM

E. Kh. Ahmed – M. A. Ameen · Tethering Monosaccharides to Thieno[2,3-d]pyrimidinones
1287
32.5 (C-6), 32.9 (Cq), 36.0 (C-20,60), 36.1 (C-8), 44.5 (Cq), 36.0 (C-20,60), 36.4 (C-8), 44.5 (N-CH2), 51.5 (CH2-
(N-CH2), 61.2 (C5H-CH2-OCO), 62.0 (CH2, ester), 66.8 N), 62.0 (CH2, ester), 118.5 (C-4a), 120.8 (CHar−triazole),
(C4H), 67.8 (C2H), 70.8 (C3H), 74.0 (C5H), 86.3 (C1H- 130.5 (C-8a), 131.3 (C-4b), 146.8 (Cq−triazole), 154.9 (C-
Ntriazole), 118.6 (C-4a), 121.7 (CHar−triazole), 130.5 (C- 9a), 158.0 (C=O), 162.0 (C=O, ester), 166.9 (C-2). – HRMS
8a), 131.4 (C-4b), 143.9 (Cq−triazole), 157.7 (C-9a), 158.0 (ESI): m/z = 726.4340 (calcd. 726.4451 for C40H64N5O3S2,
(C=O), 162.0 (C=O, ester), 166.9 (C-2), 168.9, 169.8, 169.9, [M+H]+).
170.3 (4COCH3). – HRMS (ESI): m/z = 804.2360 (calcd.
Synthesis of compound 8
804.2584 for C36H46N5O12S2, [M+H]+.
A solution of sodium ethoxide in ethanol (0.3 equiv.) was
added to a stirred solution of the glycoside tetraacetate 6a
(0.81 g, 1 mmol, 1.0 equiv.) in EtOH (10 mL) at r. t. The
mixture was stirred for 3 h (TLC showed complete conver-
sion). The precipitate that formed was filtered off, washed
3-(2-Ethoxy-2-oxoethyl)-2-[(1-(octadecyl)-1H-1,2,3-triazol-
4-yl)methyl]sulfanyl-4-oxo-3,4,5,8-tetrahydro-spirobenzo-
[b]thieno[2,3-d]pyrimidine-7(6H),10-cyclohexane (6c)
The product was obtained, following the general pro- with ethanol and crystallized from DMF-water to give com-
cedure, under stirring at r. t. for 18 h as colorless crys- pound 8 as colorless crystals. Yield 54%; m. p. 268 – 270 ◦C.
tals (0.66 g, 90%); m. p. 62 – 63 ◦C. – Rf = 0.46 (CH2Cl2- – 1H NMR (300 MHz, DMSO): δ = 1.31 (t, 6H, J = 6.4 Hz,
CH3OH, 98:2). – 1H NMR (300 MHz, CDCl3): δ = 0.82 2COOCH2CH3), 1.33 – 144 (m, 20H, 2H-20,30,40,50,60), 1.60
(t, 3H, J = 7.0 Hz, CH3), 1.20 (m, 35H, 16CH2−octadecyl
,
(t, 4H, J = 6.2 Hz, 2H-6), 2.50 (s, 4H, 2H-8), 2.78 (bs, 4H,
COOCH2CH3), 1.33 – 144 (m, 10H, H-20,30,40,50,60), 1.61 2H-5), 4.36 (q, 4H, J = 6.7 Hz, 2COOCH2CH3), 4.45 (s, 4H,
(t, 2H, J = 6.4 Hz, H-6), 1.82 (s, 2H, CH2-N), 2.51 (s, 2N-CH2). – 13C NMR (75 MHz, DMSO): δ = 13.9 (CH3),
2H, H-8), 2.88 (t, 2H, J = 5.9 Hz, H-5), 4.18 (q, 2H, 21.3 (C-30,50), 21.9 (C-5), 26.2 (C-40), 32.1 (C-6), 32.5 (Cq),
J = 7.0 Hz, COOCH2CH3,), 4.26 (bs, 2H, CH2-Ctriazole), 35.3 (C-20,60), 35.5 (C-8), 42.9 (N-CH2), 64.6 (CH2, es-
4.78 (bs, 2H, N-CH2), 7.73 (bs, 1H, CHar−triazole). – 13C ter), 116.3 (C-4b), 127.7 (C-4a), 129.2 (C-8a), 153.3 (C-
NMR (75 MHz, CDCl3): δ = 14.1 (2CH3), 21.8 (C-30,50), 9a), 157.5 (C=O), 161.3 (C-2), 169.4 (C=O, ester). – HRMS
22.2 (C-5), 22.7 (CH2CH3), 26.6 (C-40), 26.7 (CH2-C), 28.9, (ESI): m/z = 391.1233 (calcd. 391.1150 for C38H46N4O6S4,
29.4, 29.5, 29.6, 29.7, 30,1, 31.9 (15 CH2), 32.5 (C-6), 32.9 [M]2+).
[1] D. E. Cane, C. T. Walsh, C. Khosla, Science 1998, 282, [12] V. V. Rostovtsev, L. G. Green, V. V. Fokin, K. B.
63 – 68.
Sharpless, Angew. Chem. Int. Ed. 2002, 41, 2596 –
2599.
[2] K. B. Sharpless, M. G. Finn, H. C. Kolb, Angew. Chem.
Int. Ed. 2001, 40, 2004 – 2021.
[13] C. W. Tornoe, C. Christensen, M. Meldal, J. Org.
[3] H. C. Kolb, K. B. Sharpless, Drug Discovery Today
2003, 8, 1128 – 1137.
[4] P. M. Boyle, P. A. Silver, J. R. Soc. Interface 2009, 6,
S535 – S546.
[5] J. Krim, B. Sillahi, M. Taourirte, E. M. Rakib, J. W. En-
gels, Arkivoc 2009, xiii, 142 – 152.
[6] I. Pe´rez-Castro, O. Caaman˜o, F. Ferna´ndez, M. D. Gar-
c´ıa, C. Lo´pez, E. de Clercq, Arkivoc 2010, iii, 152 –
168.
Chem. 2002, 67, 3057 – 3064.
[14] L. D. Jennings, S. L. Kincaid, Y. D. Wang, G. Krish-
namurthy, C. F. Beyer, J. P. McGinnis, M. Miranda,
C. M. Discafanid, S. K. Rabindran, Bioorg. Med.
Chem. Lett. 2005, 15, 4731 – 4735.
[15] Y. D. Wang, S. Johnson, D. Powell, J. McGinnis,
M. Miranda, S. K. Rabindran, Bioorg. Med. Chem.
Lett. 2005, 15, 3763 – 3766.
[16] C. Zhao, C. Tovar, X. Yin, Q. Xu, I. T. Todorov,
L. T. Vassilev, L. Chen, Bioorg. Med. Chem. Lett.
2009, 19, 319 – 323.
[7] E. D. Goddard-Borger, V. S. Robert, Org. Lett. 2007, 9,
3797 – 3800.
[8] G. Molteni, A. Pont, Arkivoc 2006, xvi, 49 – 56.
[9] A. Xuejun, Z. Richard, P. H. Hongyan, Chem. Com-
mun. 2007, 2420 – 2422.
[17] M. A. Ameen, S. Karsten, J. Liebscher, Tetrahedron
2010, 66, 2141 – 2147.
[18] G. H. Handley, E. R. Nelson, T. C. Somers, Aust. J.
Chem. 1960, 13, 127 – 144.
[10] F. Pagliai, T. Pirali, E. Del Grosso, R. Di Brisco,
G. C. Tron, G. Sorba, A. Genazzani, J. Med. Chem. [19] I. Guareschi, Chem. Zbl. 1901, 1, 579.
2006, 49, 467 – 470. [20] I. Guareschi, Chem. Zbl. 1911, 11, 362.
[11] M. A. Ameen, S. Karsten, R. Fenger, J. Liebscher, [21] A. I. Vogel, J. Chem. Soc. 1934, 1758 – 1765.
Tetrahedron Lett. 2010, 51, 4328 – 4330.
Unauthenticated
Download Date | 3/17/17 3:20 PM

1288
E. Kh. Ahmed – M. A. Ameen · Tethering Monosaccharides to Thieno[2,3-d]pyrimidinones
[22] F. Sauter, U. Jordis, J. Fro¨hlich, K. Gewald, F. Groh- [26] V. Kesavan, D. Bonnet-Delpon, J.-P. Be´gue´, Synthesis
mann, E. K. Ahmed, ACH-Models in Chem. 1994, 131,
489 – 498.
2000, 223 – 225.
[27] I. Sucholeiki, Tetrahedron Lett. 1994, 35, 7307 –
[23] D. Wiu, Synthesis 2008, 2491 – 2509.
7310.
[24] U. Pathak, L. K. Pandey, S. Mathur, Synth. Commun. [28] F. D. Tropper, F. O. Andersson, S. Braun, R. Roy, Syn-
2009, 39, 2923 – 2927. thesis 1992, 618 – 620.
[25] S. T. A. Shah, K. M. Khan, M. Fecker, W. Voelter, [29] M. J. Marti, I. Rico, J. C. Ader, A. de Savignac, A. Lat-
Tetrahedron Lett. 2003, 44, 6789 – 6791. tes, Tetrahedron Lett. 1989, 30, 1245 – 1248.
Unauthenticated
Download Date | 3/17/17 3:20 PM