Pseudohalogenation of methyl 9-hydroxy-cis-12-and 12-hydroxy-cis-9-octadecenoate

Article abstract of DOI:10.1007/s11746-997-0206-x

Pseudohalogenation of methyl 9-hydroxy-cis-12-octadecenoate (I) and methyl 12-hydroxy-cis-9-octadecenoate (II) has been carried out with N,N-dibromobenzenesulfonamide (NNDBS). Compounds I and II, on reaction with NNDBS, formed four and three products, res

Full text of DOI:10.1007/s11746-997-0206-x

Pseudohalogenation of Methyl 9-Hydroxy-cis-12-
and 12-Hydroxy-cis-9-Octadecenoate
Fehmida Naqvia,*, Abdul Raufb, M.M. Siddiquic, M.S. Ahmad, Jr.c, and S.M. Osmanc
aDepartment of Chemistry, Jamia Millia Islamia, New Delhi 110025, India, and bApplied Sciences Section,
University Polytechnic, Faculty of Engineering and Technology, and, cSection of Oils and Fats,
Department of Chemistry, A.M.U., Aligarh 202002, India
ABSTRACT: Pseudohalogenation of methyl 9-hydroxy-cis-12-
at the β- and γ-positions relative to the unsaturation. The re-
sults of the reactions are interesting because we have been
able to isolate and characterize 1,4-epoxy compounds besides
other expected products.
octadecenoate (I) and methyl 12-hydroxy-cis-9-octadecenoate
(II) has been carried out with N,N-dibromobenzenesulfonamide
(NNDBS). Compounds I and II, on reaction with NNDBS,
formed four and three products, respectively. The interesting
feature of these reactions was the formation of 1,4-epoxy com-
pounds. The structures of individual compounds were estab-
lished with the help of elemental and spectral analysis.
JAOCS 74, 713–717 (1997).
EXPERIMENTAL PROCEDURES
Infrared (IR) spectra were obtained with a Perkin-Elmer 621
spectrophotometer (Norwalk, CT) (liquid film or 1% solution
in carbon tetrachloride). Nuclear magnetic resonance (NMR)
spectra were recorded in CCl4 with a Varian A60-NMR spec-
trometer (Palo Alto, CA) and tetramethyl silane as internal
standard. Chemical shifts were measured in ppm downfield
from the internal standard (δ = 0). The abbreviations “s, d, m,
br, t” denote singlet, doublet, multiplet, broad, and triplet, re-
spectively. Mass spectra (MS) were measured with a JEOL
JMS-D300 spectrometer (Tokyo, Japan). Thin-layer chroma-
tography (TLC) plates were coated with silica gel G (0.25 mm
thickness), and a mixture of petroleum ether/diethyl
ether/acetic acid (70:30:1, vol/vol/vol) was used as develop-
ing solvent. The spots were visualized by charring at 100°C
after spraying with a 20% aqueous solution of perchloric acid.
Petroleum ether refers to a fraction of b.p. 40–60°C.
KEY WORDS: 1,4-Epoxy fatty esters, methyl isoricinoleate,
methyl ricinoleate, NNDBS.
Advances in modification of fatty chemicals have recently
been made in various directions. Much research attention is
being directed toward the addition of a group of reagents, cat-
egorized as “pseudohalogens,” to the double bonds of
aliphatic and alicyclic compounds. A number of pseudohalo-
gens have come into prominence (1–6), viz., iodine iso-
cyanate, N,N-dichlorourethane, monochlorourethane, chlo-
rine azide, bromine azide, iodine azide, nitrosyl chloride,
nitryl iodide, N,N-dibromoacetamide, N,N-dibromobenzene
sulfonamide (NNDBS), etc.
Addition of pseudohalogens to an unsaturated system is
important (7–9) and has been known for a long time to pre-
pare a variety of derivatives. Foglia et al. (10) have investi-
gated the addition of NNDBS to internal olefins. The major
products were isomeric mixtures of β-bromosulfonamides,
while dibromide and bromohydrins were found in small
amounts. Ahmad et al. (9), Foglia et al. (10), and Nasirullah
et al. (11) reported the reaction of NNDBS with 10-unde-
cenoic, oleic, and trans-2-hexadecenoic acids. In continua-
tion of our program to derivatize fatty acids for possible in-
dustrial utilization, we report here the reaction of NNDBS
with methyl 9-hydroxy-cis-12-octadecenoate (methyl isorici-
noleate, I) and methyl 12-hydroxy-cis-9-octadecenoate
(methyl ricinoleate, II).
MATERIALS AND METHODS
Extraction of isoricinoleic and ricinoleic acids. The iso-
ricinoleic (9-hydroxy-cis-12-octadecenoic) and ricinoleic
(12-hydroxy-cis-9-octadecenoic) acids were isolated from
Wrightia tinctoria (12) and Ricinus cummunis (castor oil) by
Gunstone’s partition method (13), and the structures were es-
tablished by spectral methods (14). Methyl esters (I, II) of the
corresponding acids were prepared by using a catalytic
amount of hydrochloric acid in absolute methanol
(H+/MeOH). The acids (5.0 g) were dissolved in 5% meth-
anolic hydrogen chloride (200 mL) and refluxed for 2 h.
About two-thirds of the methanol was evaporated under re-
duced pressure. The mixture was diluted with water (100 mL)
that contained 5% sodium chloride, and the methyl ester was
extracted with diethyl ether. The ether layer was washed with
water until neutral to litmus and dried over anhydrous sodium
These reactions were performed to investigate the effect
of neighboring group participation of the hydroxyl function
*To whom correspondence should be addressed.
E-mail: shams.ch.@jmi.ernet.in.
Copyright © 1997 by AOCS Press
713
JAOCS, Vol. 74, no. 6 (1997)

714
F. NAQVI ET AL.
sulfate. The solution was filtered, and the solvent was re- with signals at 4.15); 3.68 s (3H, COOCH3), 2.2 m (2H,
moved under reduced pressure. CH2–COO CH3),+1.32 br, s (chain-CH2–) and 0.9 t (termi-
·
Preparation of NNDBS. Benzenesulfonamide (62.5 g), nal-CH3). MS: M at m/z 470/472/474 were absent, but the
sodium bicarbonate (80.0 g), and water (300 mL) were highest ion peaks appeared at m/z 399/401/403 (m-71), fol-
placed in a 1-L three-necked flask. Then, bromine (127.5 g) lowed by other important peaks at m/z 385/387/389
was added with vigorous stirring. The resulting precipitate (399/401/403-14), 369/371/373 (M-101) and 355/357/359
of NNDBS was filtered, washed with water, and dried. A yel- (369/371/373-14).
low solid was obtained (122.5 g) that melted at 114°C (lit.,
115°C) (15).
Methyl 13(12)-bromo-9,12(13)-dihydroxy-octadecanoate
(V). Analysis: calc. for C19H37O4Br: C, 55.74; H, 9.11%.
Pseudohalogenation of Ib with NNDBS. Pseudohalogena- Found: C, 55.87; H, 9.12%, IR (neat): 3420 (OH), 1735
tion of methyl isoricinoleate (I) with NNDBS was carried out (COOCH3), 1090, 1060, 1030 (C-O) and 690 cm−1 (C–Br).
according to the procedure of Foglia et al. (10). Compound I NMR (CCl4): 4.13 m(1H, CH–Br); 3.9 m (2H, 2 × CH–OH);
(4.99 g, 0.016 mol) was added dropwise to an ice-cooled so- 3.62 s (3H, COOCH3); 2.32 m (2H, 2 × CH–OH, D2O-ex-
lution of NNDBS (5.9 g, 0.016 mol) in CCl4 (35.0 mL) while changeable); 2.22 m (2H, CH2–COOCH3); 1.3 br, s (chain-
+
·
maintaining the reaction temperature at 15–20°C with contin- CH2); and 0.9 t (terminal CH3). MS: M at m/z 408/410 were
uous stirring. After adding all of the methyl isoricinoleate, absent, but the highest molecular ion peak appeared at m/z
stirring was continued further until a clear solution was 390/392 (M-18), followed by other important peaks at m/z
obtained.
359/361 (390/392-31), 280 (359/361-Br), 279 (359/361-
The reaction was monitored by TLC, and the reaction took HBr), 215 [M–CH3–(CH2)4-CH(OH)–CH(Br)–], 205/207,
about 24 h to complete. A 20% solution (25 mL) of sodium 193/195, 185, 171(185-14), 163/165, 157(171-14) and 101
bisulfite was added to the reaction mixture at room tempera- (locates the position of OH group at C13).
ture. After shaking well, the organic layer was extracted with
Methyl 9-hydroxy-12(13)-bromo-13(12)-benzene-sulfon-
CCl4 three times and dried over anhydrous sodium sulfate. amidooctadecanoate (VI) (major product 65%). Analysis:
Removal of the solvent under reduced pressure yielded a calc. for C25H42O5BrNS : C, 54.75; H, 7.72%. Found: C,
dark-brown viscous oil (7.0 g), which revealed four distinct 56.1; H, 7.8%. IR (neat): 2440 (OH), 3260 (N–H), 3050
spots on TLC. The crude mixture (4.8 g) was resolved on a (C=C–H), aromatic system, 1740 (COOCH3), 1560 (C=C),
silica gel (120 g) column, prepared in petroleum ether, and aromatic, 1335, 1160 (SO2N), 1110, 1090, 1065, 1030 (C–O)
eluted with petroleum ether/diethyl ether (96:4, vol/vol). The 755 and 720 cm−1 (C–Br). NMR (CCl4): 7.9 m (2H, C); 7.6
TLC-monitored eluates were combined to give III (0.96 g, m (3H, D), 7.1 distorted m (1H, N–H, D2O-exchangeable);
20%). Elution with petroleum ether/diethyl ether (90:10, 4.2 m (1H, CH–Br), 3.95 m (1H; CH–OH); 3.65 s 3H,
vol/vol) gave IV (0.29 g, 6%). Subsequent elution with pe- COOCH3); 3.45 m (CH–NH); 3.19 m (1H, CH–OH, D2O-ex-
troleum ether/diethyl ether (80:20, 65:35, vol/vol) furnished changeable); 2.32 m (2H, CH2–COOCH3); 1.3 br, s (chain-
V (0.19 g, 4%) and VI (3.12 g, 65%), respectively. Each com- CH2–); and 0.9 t (3H, terminal CH3), where
ponent gave a positive Beilstein test.
H
H
Methyl 9,12-epoxy-13-bromooctadecanoate (III). Analy-
C =
H
sis: calc. for C19H35O3Br: C, 58.31; H, 9.01% Found: C,
58.50; H, 9.03%. IR (neat): 1735 (COOCH3), 1110 (1,4-epox-
ide), 1180, 1155, 1060, 1020 (C–O), and 685 cm−1 (C–Br).
SO2
SO2
and D =
H
H
+
·
NMR (CCl4): 4.0 m(3H, A; 3.62 s (3H, COOCH3); 2.22 m MS: M at m/z 547/549 were absent, but the highest ion peaks
(2H, CH2–COOCH3); 1.8 m (4H, B) 1.4 br, s (chain-CH2–), appeared at m/z 404/406 (M − (CH2)6 − COOCH3), followed
and 0.9 t (terminal CH3), where
by other important peaks at m/z 402/404 (M − C8H17O2),
390/392 (404/406-14), 388/390 (402/404-14) 374/376
(390/392-16), 372/374 (390/392-18), 358/360(374/376-16 or
390/392-32), 346/348 [M − CH2·CHOH·(CH2)7·COOCH3],
332/334(346/348-14), 310/312, 308(388-HBr), 294, 279,
255/257(332/334-77), 252(332/334-HBr), 240, 227, 226,
CH2 CH2
O
Br–HC–CH
CH–
and B =
A =
O
+
·
MS: M (molecular ion peak) at m/z 390/392, followed by 221/223, 213, 195, 187, 170(187-17) 163/165, 155 (187-32),
other important peaks at m/z 359/361 (M − OCH3), 311 (M − 141, 125, and 77 (base peak).
Br), 293(311-18), 279(311-32), 263/265, 257, 241, 227, 209,
195, 177, 163/165 and 159.
Pseudohalogenation of IIb with NNDBS. Pseudohalogena-
tion of methyl ricinoleate (II) with NNDBS was carried out
Methyl 12,13-dibromo-9-hydroxyoctadecanoate (IV). in the same manner as that of methyl isoricinoleate (I), de-
Analysis: calc. for C19H36O3Br2: C, 48.32; H, 7.68%. Found: scribed earlier. Direct TLC of the resulting oily product re-
C, 48.51; H, 7.71%. IR (neat): 3450 (OH), 1735 (COOCH3), vealed three distinct spots. The product mixture (4.6 g) was
1195, 1160, 1110, 1010 (C–O), and 690 cm−1 (C–Br), NMR chromatographed over a silica gel (120 g) column. Elution
(CCl4): 4.3 m (1H, OH, D2O exchangeable); 4.15 m (2H, with mixtures of petroleum ether/diethyl ether, 92:8, 80:20
Br–CH(–)CH(–)–Br); 3.9 m (1H, –CH–OH, in parts merged and 65:35 (vol/vol), gave VII (0.87 g, 19%), VIII (0.23 g,
JAOCS, Vol. 74, no. 6 (1997)

PSEUDOHALOGENATION OF β- AND γ-HYDROXY OLEFINIC ACID ESTER
715
5%), and IX (3.22 g, 70%), respectively. Each fraction
showed a positive test for halogen.
RESULTS AND DISCUSSION
Methyl 9,12-epoxy-10-bromooctadecanoate (VII). Analy-
sis: calc. for C19H35O3Br: C, 58.31; H, 9.01%. Found: C,
58.5; H, 9.05%. IR (neat): 1735 (COOCH3), 1170, 1080,
1040, 1020 (C–O) and 730 cm−1 (C–Br). NMR (CCl4):
4.5–3.9 br, m (3H, E), 3.65 s (3H, COOCH3); 2.25 m
CH2–COOCH3); 1.65 (2H, F); 1.35 br, s (chain-CH2–); and
0.88 t (3H, terminal CH3), where
The reaction of NNDBS with methyl 9-hydroxy-cis-12-oc-
tadecenoate (I, methyl isoricinoleate) and methyl 12-hy-
droxy-cis-9-octadecenoate (II, methyl ricinoleate) was car-
ried out by following the method of Foglia et al. (10). Com-
pound I on reaction with NNDBS gave four products
(III–VI), which responded positively toward the Beilstein
test (Scheme 1). The IR spectrum of III revealed no band for
an OH group in the region 3650–3200 cm−1, indicating the
absence of a free OH group. This suggested that neighboring
group participation has taken place. Other bands were ob-
served at 1735 (COOCH3), 1110 (1,4-epoxide), 1180, 1155,
1060, 1020(C–O) and 685 cm−1 (C–Br). The PMR spectrum
of III exhibited structure-revealing signals at δ 4.0 m (3H, A)
and 1.8 m (4H, B), along with the characteristic signals of
fatty esters at 3.62 s (3H, COOCH3), 2.22 m (2H,
CH2–COOCH3), 1.4 br, s (chain-CH2) and 0.9 t (3H, terminal
CH3), where A and B are as given above. The mass spectrum
of III provided further support to its structure. Mass spectrum
III gave molecular ion peaks at m/z 390/392 with other sig-
nificant peaks at m/z 359/361 (M − OCH3); 311 (M − Br); 293
(311-18); 279 (311-32); 263/265; 257; 241; 209; 195; 177;
163/165 and 159. Thus, in light of the above spectra data and
mass fragmentation pattern, the structure of III was estab-
lished as methyl 13-bromo-9,12-epoxyoctadecanoate.
H
Br
Br
H
H
and F =
E =
H
O
O
H
Methyl 9,10-dibromo-12-hydroxyoctadecanoate (VIII).
Analysis: calc. for C19H35O3Br2: C, 48.32; H, 7.68% Found:
C, 48.6, H, 7.7%. IR (neat): 3500 (OH), 1735 (COOCH3),
1170, 1080, 1020 (C–O) and 720 cm−1 (C–Br). NMR (CCl4):
4.2 m (2H, Br–CH(–)–CH(–)–Br); 4.0 m (1H, –CH–OH);
3.65 s (3H, COOCH3); 2.85 br, s (1H, CH–OH, D2O-ex-
changeable); 2.32 m (2H, CH2–COOCH3) 1.35 br, s (chain-
CH2–) and 0.92 t (3H, terminal CH3).
Methyl 12-hydroxy-9(10-bromo-10(9)-benzenesulfonami-
doctadecanoate (IX). Analysis: calc. for C25H42O5BrNS: C,
54.74; H, 7.72; N, 2.55%. Found: 54.91; H, 7.81; N, 2.45%.
IR (neat): 3470 (OH), 3275 (N–H), 3075 (C=C–H, aromatic
system), 1735 (COOCH3), 1501 (C=C, aromatic) 1335, 1160
(C–SO2N), 1110, 1090, 1055, 1030 (C–O), 770 and 710 cm−1
(C–Br). NMR (CCl4); 7.85 m (2H, C), 7.55 m (3H, D), 7.1
distorted m (1H, N–H, D2O-exchangeable), 4.25 m (1H,
CH–Br), 3.95 m (1H, CH–OH), 3.72 s (3H, COOCH3), 3.51
The IR spectrum of IV showed bands at 3450 (OH), 1735
(COOCH3), 1195, 1160, 1110, 1010(C-O) and 690 cm−1
(C–Br). The PMR spectrum of this compound gave important
signals at δ 4.3 m (1H, OH, D2O-exchangeable), 4.15 m, (2H,
Br–CH(–)–CH(–)–Br), 3.9 m (1H, CH, OH in part merged
with signals at δ 4.15), along with the usual signals for fatty
esters. This suggests that the addition of bromine to the dou-
ble bond of the ester has taken place.
m
(1H, CH–OH, D2O-exchangeable) 2.35 m (2H,
CH2–COOCH3), 1.35 br, s (chain-CH2), and 0.9 t (3H, termi-
nal CH3), where C and D are explanined above.
Further support to the structure of dibromo ester was pro-
R − CH = CH − R′
(I)
NNDBS
(CH2)7COOCH3
R − CH – CH − R′
R − CH — CH − R′ R − CH – CH − R′
R-CH
Br
O
Br Br
Br/OH OH/Br
Br/x x/Br
(III)
(IV)
(V)
(VI)
R = (CH2)2-CH(CH2)7-COOCH3, R′ = (CH2)2-CH(CH2)7-COOCH3-COOCH3, X = NHSO2C6H5
OH
OH
NNDBS = C6H5SO2NBr2
SCHEME 1
JAOCS, Vol. 74, no. 6 (1997)

716
F. NAQVI ET AL.
vided by its mass-spectral studies. The mass spectrum of IV nals for fatty esters. These spectral data indicated the pres-
showed absence of molecular ion peaks at m/z 470/472/474, ence of hydroxybromo and benzene sulphonamide moieties
and the highest molecular ion peaks were observed at m/z in the molecule. This could be attributed to the addition of
399/401/403 (M − 14), followed by other important peaks at NNDBS across the double bond. This compound was also ex-
m/z 385/387/389 (399/401/403-14), 369/371/373 (M-101), pected to be an isomeric mixture of methyl 9-hydroxy-12-
355/357/359 (369/371/373-14). Thus, on the basis of above bromo-13-benzenesulfonamidooctadecanoate and methyl 9-
evidence, compound IV was characterized as methyl 12,13- hydroxy-13-bromo-12-benzenesulfonamidooctadecanoate.
dibromo-9-hydroxyoctadecanoate.
Further confirmation of the structure of compound VI was
The IR spectrum of V gave bands at 3420(OH), 1735 obtained with the help of mass-spectral studies. The mass
(COOCH3), 1090, 1060, 1030 (C–O) and 690 cm−1 (C–Br). spectrum of the compound showed no molecular ion peaks at
PMR of this compound revealed important signals at δ 4.13 m/z 547/549, but again the highest molecular ion peaks ap-
m (1H, –CH-Br), 3.9 m (2H, 2 × CH–OH), 2.32 m (2H, 2 × peared at m/z 404/406 [M − (CH2)6–COOCH3], along with
CHOH, D2O-exchangeable), along with other peaks typical other significant peaks at m/z 402/404 (M − C8H17O2),
for fatty esters. The IR and PMR data suggested that com- 390/392 (404/406-14); 388/390 (402/406-14), 374/376
pound V was a simple bromohydrin derivative of methyl (390/392-16); 373/374 (390/392-18); 358/360 (374/376-16
isoricinoleate. The formation of bromohydrin is not unusual or 390/392-32); 346/348 [M − CH2CHOH(CH2)7COOCH3];
because it has been reported that the reaction of NNDBS with 332/334 (346/348-14); 310/312; 308 (388-HBr); 294, 297,
olefins results in the formation of bromohydrins as minor re- 255/257 (332/334-77); 252 (332/334-HBr); 240; 227; 226;
action products (16).
221/223; 213; 195; 187; 170 (187-17); 163/165; 155 (187-
Compound V was expected to be an isomeric mixture of 32); 141; 125 and 77 (base peak, 100%).
methyl 13-bromo-9,12-dihydroxyoctadecanoate and methyl
A similar reaction of NNDBS and methyl 12-hydroxy-cis-
12-bromo-9,13-dihydroxyoctadecanoate. This was supported 9-octadecenoate (II, methyl ricinoleate) afforded three prod-
by mass spectrometry. The mass spectrum of V showed the ucts (VII–IX), which showed positive Beilstein tests for the
absence of molecular ion peaks at m/z 408/410, and the high- presence of halogen (Scheme 2).
est molecular ion peaks appeared at m/z 390/392 (M − 18).
Compound VII analyzed for C19H35O3Br, (positive Beil-
Other significant peaks were noticed at m/z 359/361 stein test). The IR spectrum of VII showed no band at 3400
(390/392-31); 280 (359/361-Br); 279 (359/361-HBr), 215 cm−1, indicating the absence of a free OH group. This sug-
[M–CH3–(CH2)4–CH(OH)–(Br)–]; 205/207 (193/195); 185; gested that neighboring group participation might have oc-
171(185-14), 163/165; 157(171-14) and 101 (locates the po- curred. Other bands were observed at 1735 (COOCH3), 1170,
sition of the OH group at C13).
1080, 1040, 1020 (C–O), and 730 cm−1 (C–Br). The NMR
The IR spectrum of VI showed bands at 3440 (OH), 3260 spectrum of the compound (VII) gave structure-revealing sig-
(N-H), 3050 (C=C–H, aromatic system), 1740 (COOCH3), nals at 4.5–3.9 br, m (3H, E) and 1.65 (2H, F), along with the
1560 (C=C, aromatic), 1335; 1160 (SO2N), 1110, 1090; 1065; usual signals of fatty esters, where E and F are explained
1030 (C–O), 755 and 720 cm−1 (C–Br). PMR of this com- above. Thus, on the basis of these elemental and spectral data,
pound revealed important signals at δ 7.9 m (2H, C) 7.6 m VII was characterized as methyl 9,12-epoxy-10-bromo-octa-
(3H, D); 7.1 distorted m (1H, N–H, D2O exchangeable), 4.2 decanoate.
m (1H, CH–Br) and 3.95 m (1H, CHOH) along with usual sig-
Microanalysis of VIII gave the composition C19H36O3Br2
R − CH = CH − R′
(II)
NNDBS
Br
R
R − CH – CH − R′
R − CH – CH − R′
CH3(CH2)5
O
Br Br
Br/x x/Br
(VII)
(VIII)
(IX)
R′ = (CH2)7COOCH3
R = CH3(CH2)5CHCH2-
OH
X = NHSO2C6H5
SCHEME 2
JAOCS, Vol. 74, no. 6 (1997)

PSEUDOHALOGENATION OF β- AND γ-HYDROXY OLEFINIC ACID ESTER
717
for providing facilities, and UGC (New Delhi) for rendering finan-
cial support to F. Naqvi.
(positive Beilstein test). The composition suggested that
bromination of the double bond has taken place. Its IR spec-
trum showed bands at 3500 (OH), 1735 (COOCH3), 1170,
1080, 1020 (C–O) and 720 cm−1 (C–Br). The NMR of this
compound gave signals at 4.2 m (2H, Br–CH(–)–CH(–)–Br),
4.0 m (1H,–CH(OH)–), 2.85 br, s (1H, –CH–OH, D2O-ex-
changeable). In light of these elemental and spectral data,
compound VIII was characterized as methyl 9,10-dibromo-
12-hydroxy-octadecanoate.
Compound IX corresponded to formula C25H42O5BrNS
(positive Beilstein test). Its IR spectrum revealed bands at
3470 (OH), 3275 (N–H), 3075 (C=C–H, aromatic system),
1735 (COOCH3), 1501 (C=C, aromatic), 1335, 1160
(C–SO2N), 1110, 1090, 1055, 1030 (C–O), 770 and 710 cm−1
(C–Br). NMR of IX showed important signals at 7.85 m (2H,
G), 7.5 m (3H, H), 7.1 distorted m (1H, N–H, D2O-exchange-
able), 4.25 m (1H, CH–Br), 3.95 m (1H, CH–OH), 3.51 m
(1H, CH–OH, D2O-exchangeable), along with the usual sig-
nals of fatty esters, where
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Nitrosochlorination of Olefinic Fatty Acids: I, J. Am. Oil Chem.
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7. Buckless, R.E., and W.J. Probst, Reactions of N-Bromoamides
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(1957).
8. Oehlschldger, A.C., C.D. Kennedy, and L.H. Zalkow, Bridged
Ring Compounds. XIII. The Reaction of N,N-Dibromobenzene-
sulfonamide with Bicyclo [2.2.1] Heptene, Bicyclo [2.2.2]
Octene, and Endo-Bicyclo [2.2.1]-5-Heptene-2,3-Dicarboxylic
Anhydride, Ibid. 31:1682–1688 (1966).
H
H
and H =
G =
H
H
H
These elemental and spectral data established the structure of
IX as methyl 12-hydroxy-9(10)-bromo-10(9)-benzenesulfon-
imidooctadecanoate.
9. Ahmad, F., Nasirullah, S.F. Siddiqui, and S.M. Osman, Addi-
tion of N,N-Dibromobenzene Sulfonamide to a Terminal Fatty
Acid I, Fette Seifen Astrichm. 82:268–271 (1980).
10. Foglia, T.A., E.T. Haeberer, and G. Maerker, Addition of N,N-
Dibromosulfonamides to Internal Olefins: Synthesis of Sulfony-
laziridines, J. Am. Oil Chem. Soc. 47:27–32 (1970).
11. Nasirullah, F. Ahmad, and S.M. Osman, Addition of N,N-Di-
bromobenzenesulfonamide to Methyl Oleate, Elaidate and
trans-2-Hexadecenoate II, Fette Seifen Anstrichm. 86:51–55
(1984).
12. Ansari, F.H., G.A. Qazi, S.M. Osman, and M.R. Subbaram, Oc-
currence of Strophanthus Acid in Two Wrightia Fats (Apocy-
naceae), Indian H. Appl. Chem. 34:157–160 (1971).
13. Gunstone, F.D., Fatty Acids, Part II. The Nature of Oxygenated
Acid Present in Vernonia anthelmintica (wild) Seed Oil, J.
Chem. Soc.:1611–1616 (1954).
14. Ahmad, M.U., S.K. Husain, and S.M. Osman, Ricinoleic Acid
in Phyllanthus niruri Seed Oil, J. Am. Oil Chem. Soc.
58:673–674 (1981).
15. Akiyoshi, S., and K. Okuno, The Synthesis of α-Alkoxy β-
Haloethyl Acetates and 2-Aminothiazole, J. Am. Chem. Soc.
76:693–694 (1954).
Pseudohalogenation with NNDBS appears to be in confor-
mity with the accepted mechanism of electrophilic addition
to the carbon-carbon double bond and involves a cyclic
bromonium ion intermediate. The initial attack of bromine
ion produces a cyclic bromonium ion intermediate. This in-
termediate, unlike other similar intermediates from internal
olefins, offers an opportunity for preferential attack of the an-
ionic part of the reagent (nucleophile) from an unhindered
methylene side, thus, resulting in the almost exclusive forma-
tion of addition products. The formation of dibromides and
bromohydrins in reactions of NNDBS with olefins has been
supported by an earlier report (10). The reaction of NNDBS
with 12- and 9-hydroxy-olefinic (ricinoleic and isoricinoleic)
acid has been proved to be a convenient route to synthesis of
tetrahydrofuran (1,4-epoxide) derivatives. The formation of
the tetrahydrofuran could be rationalized by neighboring
group participation of the hydroxy function.
16. Wolfe, S., and D.V.C. Awang, Allylic Bromination by N-Bro-
moacetamide, Ibid. 89:5287–5288 (1967).
ACKNOWLEDGMENTS
The authors express their sincere thanks to the department chairman
[Received April 8, 1996; accepted February 10, 1997]
JAOCS, Vol. 74, no. 6 (1997)