Hypervalent iodine oxidation of α-substituted 2,4-dihydroxyacetophenones: Synthesis of novel o-iodophenoxy ethers via rearrangement of iodonium ylides

Article abstract of DOI:10.1139/v99-097

α-Substituted 2,4-dihydroxyacetophenones (1a-1i) have been oxidized with phenyliodonium diacetate (PIDA) under three conditions (i) PIDA-KOH-MeOH (basic) at 0°C, (ii) PIDA-MeOH (neutral) at reflux temperature, and (iii) PIDA-AcOH (acidic) at reflux temper

Full text of DOI:10.1139/v99-097

1191
Hypervalent iodine oxidation of ␣-substituted
2,4-dihydroxyacetophenones: synthesis of novel
o-iodophenoxy ethers via rearrangement of
iodonium ylides
Om Prakash, Vijay Sharma, and Madan P. Tanwar
Abstract: α-Substituted 2,4-dihydroxyacetophenones (1a–1i) have been oxidized with phenyliodonium diacetate (PIDA)
under three conditions (i) PIDA–KOH–MeOH (basic) at 0°C, (ii) PIDA–MeOH (neutral) at reflux temperature, and
(iii) PIDA–AcOH (acidic) at reflux temperature, to afford novel o-iodophenoxy ethers (4a–4i) via rearrangement of
respective iodonium ylides (5a–5i).
Key words: hypervalent iodine reagents, phenyliodonium diacetate, α-substituted 2,4-dihydroxyacetophenones,
α-substituted 2-hydroxy-3-iodo-4-phenoxyacetophenones, iodonium ylides rearrangement.
Résumé : On a oxydé des 2,4-dihydroxyacétophénones α-substituées (1a–1i) à l’aide du diacétate de phényliodonium
(« PIDA ») dans trois conditions : (i) PIDA–KOH–MeOH (basique), à 0°C; (ii) PIDA–MeOH (neutre), à la
température de reflux et (iii) PIDA–AcOH (acide), à la température de reflux; ces oxydations conduisent à de
nouveaux éthers o-iodophénoy (4a–4i) par le biais d’un réarrangement des ylures d’iodonium respectifs (5a–5i).
Mots clés : réactifs hypervalents de l’iode, diacétate de phényliodonium, 2,4-dihydroxyacétophénones α-substituées,
2-hydroxy-3-iodo-4-phénoxyacétophénones α-substituées, réarrangement d’ylures d’iodonium.
[Traduit par la Rédaction] Prakash et al. 1195
Introduction
10) (eq. [2]). On the other hand, hypervalent iodine oxida-
tion of various phenols has provided attractive routes for the
synthesis of valuable p-quinones, o-quinones, quinone
acetals, etc., which are otherwise difficult to obtain (eq. [3])
(11, 12).
A surge of interest in the use of hypervalent iodine re-
agents in organic synthesis has been witnessed by its explo-
sive growth during few last decades (1–5). Major areas of
interest are hypervalent iodine oxidation of carbonyl com-
pounds (4), phenolic oxidations (2a, 5), oxidative rearrange-
ments (1e), etc. These studies have provided a large number
of new and convenient methods for the synthesis of a wide
variety of organic compounds, including various heterocyc-
lic compounds and bridgehead compounds (3, 6).
X
OH
X
O
OMe
R'
PIDA/KOH
MeOH
[2]
CH2R
O
Y
O
Y
A notable hypervalent iodine oxidation of enolizable ke-
tones with PIDA and potassium hydroxide in methanol leads
to the formation of α-dimethylacetals (7, 8) (eq. [1]). How-
ever, the presence of a phenolic group at the ortho position
of ketones such as acetophenone, etc. affords coumaran-3-
ones by intramolecular participation in this oxidation (9,
OH
R
O
R
R
R
R
PIDA
ROH
[3]
R
OMe
OMe
PIDA/KOH
Results and discussion
[1]
R
CO
CH2
R'
R
C
CH
OH
R'
MeOH
OMe
Based upon these observations, we became interested in
oxidizing those compounds containing ortho and para phe-
nolic groups and an enolizable ketonic moiety, for example,
5-acetyl-2,4-dihydroxyacetophenone (1a), with phenyliodon-
ium diacetate (PIDA) and KOH in MeOH. The attempted re-
action yielded a yellow crystalline solid (mp 143–145°C;
yield 75%), which separated out during the stirring of the re-
action mixture. Instead of obtaining bis-coumaranones 2 (via
a route analogous to eq. [2]) or compound 3 (via a route
analogous to eq. [3]), interestingly, a novel formation of 5-
Received April 7, 1998.1
O. Prakash,2 V. Sharma, and M.P. Tanwar. Department of
Chemistry, Kurukshetra University, Kurukshetra, 136 119,
Haryana, India.
1Revision received March 7, 1999.
2Author to whom correspondence may be addressed.
e-mail: kuru@doe.ernet.in
Can. J. Chem. 77: 1191–1195 (1999)
© 1999 NRC Canada

1192
Can. J. Chem. Vol. 77, 1999
Table 1. Physical data for 4a–4i, 5c, and 5g.
Compound no.
X
R
Melting point (°C)
Yield (%)a
(i)b
(ii)b
(iii)b
4a
4b
4c
4d
4e
4f
4g
4h
4i
COCH3
H
NO2
Br
H
H
H
H
CH3
CH3
CH3
CH3
C6H5
H
143–145
116–118
190–191
160–161
136–138
119–120
190–192
146–147
129–130
>200
75
20
77
35
68
75
48
38
65
82
56
40
10
40
10
40
40
27
10
52
—
—
64
15
60
25
55
60
41
20
58
—
—
H
COC2H5
NO2
Br
H
NO2
NO2
5c
5g
CH3
196–198
aYields are based upon the pure products.
bReaction conditions: (i) PIDA – KOH in MeOH; (ii) PIDA–MeOH; (iii) PIDA–AcOH.
Scheme 1.
Scheme 2.
OMe
OMe
O
O
I
Ph
HO
OH
O
(i)
MeO
MeO
HO
X
OH
O
X
OH
X
PIDA/KOH/MeOH
O
O
2
O
R
R
1a
(i)
O
X
O
I
1a-i
5a-i
PhO
OH
O
(Isolablewhen
X = NO2)
X
(i)
1, 4, 5
R
HO
O
O
O
I
a
b
c
d
e
f
g
h
i
H
H
H
H
CH3
CH3
CH3
CH3
C6H5
COCH3
H
NO2
Br
H
COC2H5
NO2
Br
O
4a
PhO
X
OH
(i) PIDA/KOH-MeOH
OMe
R
3
O
4a-i
H
acetyl-2-hydroxy-3-iodo-4-phenoxyacetophenone (4a) was
observed (Scheme 1).
A preliminary account of this study was reported earlier
(13). This observation, coupled with the fact that the rear-
ranged products from this reaction i.e., o-iodo ethers, are po-
tential precursors for the synthesis of a variety of interesting
compounds such as dibenzofurans, which are associated
with diverse physiological activities (14), prompted us to
study the scope of this novel route.
In the present study, a full account of our detailed investi-
gations on the oxidation of α-substituted 2,4-dihydroxy-
acetophenones (4a–4i) with phenyliodonium diacetate under
different conditions is described.
Accordingly, we first carried out oxidation of 2,4-dihydro-
xyacetophenones (1b–1d) with PIDA – KOH in MeOH, to
afford the corresponding rearranged o-iodo ethers (4b–4d).
This rearrangement occurred via the intermediacy of
iodonium ylides of the type 5b–5d as evidenced by the iso-
lation of ylide 5c as a high-melting yellow solid, from the
oxidation of ketone 1c. Acidification of 5c with hydrochloric
acid, followed by refluxing the methanolic solution of the
resultant solid (mp 153–154°C), afforded a rearranged prod-
uct 4c (mp 190–191°C; yield 77%). However, our attempt to
isolate similar intermediates 5a, 5b, 5d in other cases ended
up with no success, as only the rearranged products 4a, 4b,
4d were obtained from these reactions. The physical data for
the products 4a–4d are listed in Table 1.
Similarly, oxidation of 2,4-dihydroxy-5-nitropropiophen-
one (1g) with PIDA with KOH in MeOH at 0°C (condition
(i)) afforded iodonium ylide 5g as a yellow crystalline solid
1
(based on H NMR and mp). This ylide, on acidification
with hydrochloric acid followed by refluxing, gave 2-
hydroxy-3-iodo-4-phenoxy-5-nitroacetophenone (4g) in 48%
yield.
2,4-dihydroxypropiophenone (1e), 2,4-dihydroxy-5-propionyl-
propiophenone (1f), 5-bromo-2,4-dihydroxypropiophenone (1h),
and 2,4-dihydroxydeoxybenzoin (1i) also underwent smooth
transformation to 2-hydroxy-3-iodo-4-phenoxypropiophenone
(4e) 2-hydroxy-3-iodo-4-phenoxy-5-propionylpropiophenone
(4f), 5-bromo-2-hydroxy-3-iodo-4-phenoxypropiophenone (4h),
and 2-hydroxy-3-iodo-4-phenoxydeoxybenzoin (4i), respec-
tively. The intermediates, iodonium ylides 5e, 5f, 5h, and 5i,
could not be isolated.
In view of the marked effect of conditions on the course
of various hypervalent iodine-mediated transformations, it
was considered worthwhile to investigate the role of other
reaction conditions on the oxidation of compounds 1a–1i.
© 1999 NRC Canada

Prakash et al.
1193
Scheme 3.
Scheme 4.
I
OMe
Ph
PhO
X
OH
O
HO
OH
O
MeO
I
PIDA/MeOH
(condition ii)
R
X
R
PhI (OA c)2
K O
OH
O
HO
OH
O
KOH/MeOH
1a-i
(
4a-i
PIDA/AcOH
X
R
X
R
PhI (OM e)2
(condition iii)
6
1
1, 4
R
X
1, 4
R
X
a
b
c
d
e
H
H
H
H
COCH3
H
NO2
Br
H
f
CH3
CH3
CH3
C6H5
COC2H5
NO2
Br
g
h
i
MeO
O
I
Ph
I
Ph
H
H
OH
CH3
O
OH
-MeOH
X
R
X
R
Thus substrate 1a was also oxidized with PIDA under
condition (ii), viz. PIDA in methanol (neutral) at reflux tem-
perature, and under condition (iii), PIDA in acetic acid
(acidic) at reflux temperature (Scheme 3). The product, ob-
tained after the usual work-up under these conditions, was
characterized as 4a, which was found to be identical to that
prepared under reaction condition (i). However, yields of the
products were found to be lower in conditions (ii) and
(iii) than in condition (i).
Similarly, applying conditions (ii) and (iii), other phenolic
ketones 1b–1i were oxidatively rearranged to the corre-
sponding o-iodophenoxy ethers 4b–4i. The physical data for
the products (% yields and melting points under different
conditions) are given in Table 1.
A plausible mechanistic pathway for 1÷4 via rearrange-
ment of iodonium ylide (15, 16) of type 5 is outlined in
Scheme 4. Under strong basic conditions (KOH in MeOH)
PIDA is converted into dimethoxyiodobenzene (17),
(PhI(OMe)2), while substrate 1 changes in situ into the cor-
responding potassium phenolate 6. Dimethoxyiodobenzene
attacks at position 3 of phenolate 6 to form intermediate 7,
which loses methanol to produce iodonium ylide 5. The
iodonium ylide 5 finally rearranges to product 4. It is to be
noted that under conditions (ii) and (iii) the electrophilic at-
tack of PIDA itself takes place, on substrate 1 (in place of
dimethoxyiodobenzene), to afford the final product via inter-
mediates of type 5 and 7. Since PIDA in acetic acid gives
the products in lower yields (5–18%), basic conditions pre-
sumably assist the removal of a proton from intermediate 7.
Thus PhI(OMe)2 may not be an obligatory reagent for the
products 4 and 5.
It is relevant to mention that while our detailed investiga-
tion of this rearrangement was in progress and a preliminary
communication had also appeared (13), Mallik and Mallik
reported the oxidation of 2,4-dihydroxyacetophenone and
other phenolic ketones with PIDA–MeOH at reflux tempera-
ture to afford o-iodophenoxy ethers (18). Although these re-
action conditions also afforded the same o-iodo ethers 4,
PIDA – KOH in MeOH (our condition i) gave better results
in terms of yields and isolation of products.
O
O
7
I
I
Ph
OH
PhO
OH
O
O
rearrangement
X
R
X
R
O
4
5
tional methods. The most striking feature of this approach is
that the enolizable ketonic group present in compounds 1a–
1i remains unaffected under these reaction conditions, which
normally oxidize the α-position of the enolizable ketones (7,
8). Another noteworthy feature of this oxidative rearrange-
ment is that phenolic ketones having electron-withdrawing
substituents (COCH2R and NO2) at the 5-position yield
better results. The products obtained from this study are po-
tential precursors of various organic compounds, especially
heterocyclic compounds. For example, o-iododiaryl ethers
are useful intermediates for dibenzofuran synthesis as they
could be readily cyclized either photochemically (15) or
chemically through the use of Ph(II) salts(16), n-Bu3SnH–
AIBN (19), etc.
Experimental
Melting points were measured in open capillaries in a sul-
furic acid bath and are uncorrected. IR spectra were re-
corded on a Beckmann IR-20 spectrophotometer. H NMR
1
spectra were taken on a Perkin Elmer (90 MHz) instrument.
EI mass spectra were recorded on a mass spectrophotometer
operating at 70 eV. 2,4-Dihydroxyacetophenone (1b) (20) and
its analogues (5-bromo-2,4-dihydroxyacetophenone (1d) (21),
2,4-dihydroxy-5-nitroacetophenone (1c) (22), 5-acetyl-2,4-
dihydroxyacetophenone (1a) (20, 21)), 2,4-dihydroxypropio-
phenone (1e) (20) and its analogues 5-bromo-2,4-dihydroxy-
propiophenone (1h) (23), 2,4-dihydroxy-5-nitropropiophenone
(1g) (22a), 5-propionyl-2,4-dihydroxypropiophenone) (1f)
(21), and 2,4-dihydroxydeoxybenzoin (1i) (24) were pre-
pared according to literature procedure.
Finally, the formation and rearrangement of phenolic
iodonium ylides containing an enolizable ketone moiety of-
fers a novel route for the synthesis of new o-iodophenoxy
ethers that are otherwise difficult to prepare using conven-
© 1999 NRC Canada

1194
Can. J. Chem. Vol. 77, 1999
Oxidation of 5-substituted 2,4-dihydroxyacetophenones
(1a–1d), 5-substituted 2,4-dihydroxypropiophenones
(1e–1h), and 2,4-dihydroxydeoxybenzoin (1i) with
phenyliodonium diacetate – potassium hydroxide in
methanol (condition i). General procedure
Oxidation of 5-substituted 2,4-dihydroxyacetophenones
(1a–1d), 5-substituted 2,4-dihydroxypropiophenones
(1e–1h), and 2,4-dihydroxydeoxybenzoin (1i) with
phenyliodonium diacetate in acetic acid (condition iii).
General procedure
PIDA (0.01 mol) was added to a solution of 5-substituted
2,4-dihydroxyacetophenone, 5-substituted 2,4-dihydroxypro-
piophenone, or 2,4-dihydroxydeoxybenzoin 1 (0.01 mol) in
acetic acid (20 mL) and the reaction mixture was refluxed.
The progress of the reaction was monitored by TLC. After
about 8 h the solvent was removed in vacuo. To the result-
ing mixture was added water, followed by extraction with
dichloromethane (3 × 50 mL). The combined organic ex-
tracts were washed with water and dried over anhydrous so-
dium sulphate. The solvent was distilled at reduced pressure
to obtain the crude product, which was purified by passing
through a column using silica gel (60–120 mesh size) and
petroleum ether – ethyl acetate (10:1) as an eluent to afford
pure product 4.
To a stirred solution of potassium hydroxide (0.03 mol) in
methanol (20 mL) at 0°C in a conical flask placed in an ice
bath was added 5-substituted 2,4-dihydroxyacetophenone, 5-
substituted 2,4-dihydroxypropiophenone, or 2,4-dihydroxy-
deoxybenzoin (1) (0.01 mol). PIDA (0.011 mol) was slowly
added to the resulting solution and the stirring was contin-
ued overnight. Water was added to the resulting reaction
mixture followed by dilute HCl. Subsequently, the mixture
was extracted with dichloromethane (3 × 50 mL). The com-
bined organic phases were washed with water and dried over
anhydrous sodium sulphate. The solvent was distilled off at
reduced pressure. The crude product, so obtained, was puri-
fied by passing through a column using silica gel (60–120
mesh size) and ethyl acetate – petroleum ether (1:10) as
eluent to afford pure product 4.
The physical data of the pure products are listed in
Table 1.
The yields and melting points of products 4a–4i are given
in Table 1.
Spectral and analytical data of products 4a–4i
Isolation of iodonium ylides 5c and 5g
5-Acetyl-2-hydroxy-3-iodo-4-phenoxyacetophenone (4a): IR
(Nujol, cm–1): 1630, 1670 (C=O). 1H NMR (CDCl3) δ:
2.47 (s, 3H, C1-COCH3), 2.72 (s, 3H, C5-COCH3), 6.80–
7.42 (m, 5H, C4-OC6H5), 8.45 (s, 1H, C6-H). MS
(70 eV) m/z: 396 (M+, 34), 305 (26), 303 (100), 287 (9).
Anal. calcd. for C16H13IO4: C 48.48, H 3.28; found: C
48.34, H 3.35.
To a stirred solution of potassium hydroxide (1.680 g,
0.03 mol) in methanol (20 mL) at 0°C in a conical flask
placed in an ice bath was added 2,4-dihydroxy-5-nitroace-
tophenone (1c, 1.970 g, 0.01 mol) or 2,4-dihydroxy-5-nitro-
propiophenone (1g, 2.110 g, 0.01 mol). The reaction mixture
was stirred for 10 min. PIDA (3.542 g, 0.011 mol) was
added slowly to the resulting solution and the stirring was
continued for half an hour. A yellow crystalline solid (sepa-
rated out of the solution) was isolated by filtration, followed
by washing with methanol. 5c: yield, 3.272 g, 82%, mp
2-Hydroxy-3-iodo-4-phenoxyacetophenone (4b): IR (Nujol,
1
cm–1): 1625 (C=O). H NMR (CDCl3) δ: 2.60 (s, 3H, C1-
COCH3), 6.25 (d, 1H, C5-H, J = 8.9 Hz), 7.00–7.50 (m, 5H,
C4-OC6H5), 7.63 (d, 1H, C6-H). Anal. calcd. for C14H11IO3:
C 47.45, H 3.10; found: C 47.14, H 2.80.
1
>200°C. 5g: yield 2.312 g, 56%, mp 196–198°C; H NMR
(DMSO) δ: 1.2 (t, 3H, C1-COCH2CH3), 2.97(q, 2H, C1-
COCH2CH3), 6.70–7.25(m, 5H, C4-I-C6H5), 8.6(s, 1H, C6-H).
2-Hydroxy-3-iodo-5-nitro-4-phenoxyacetophenone (4c): IR
1
(Nujol, cm–1): 1645 (C=O). H NMR (CDCl3) δ: 2.70 (s,
3H, C1-COCH3), 6.80–7.32 (m, 5H, C4-OC6H5), 8.50 (s, 1H,
C6-H), 13.30 (bs, 1H, C2-OH). Anal. calcd. for C14H10NIO5:
C 42.10, H 2.50; found: C 41.39, H 2.45.
Oxidation of 5-substituted 2,4-dihydroxyacetophenones
(1a–1d), 5-substituted 2,4-dihydroxypropiophenones
(1e–1h), and 2,4-dihydroxydeoxybenzoin (1i) with
phenyliodonium diacetate in methanol (condition ii).
General procedure
5-Bromo-2-hydroxy-3-iodo-4-phenoxyacetophenone (4d): IR
1
(Nujol, cm–1): 1630 (C=O). H NMR (CDCl3) δ: 2.20 (s,
PIDA (0.01 mol) was added to a solution of 5-substituted
2,4-dihydroxyacetophenone, 5-substituted 2,4-dihydroxypro-
piophenone, or 2,4-dihydroxydeoxybenzoin 1 (0.01 mol) in
methanol (20 mL) and the reaction mixture was refluxed.
The progress of the reaction was monitored by TLC. After
about 12 h the solvent was removed in vacuo To the result-
ing mixture was added water, followed by extraction with
dichloromethane (3 × 50 mL). The combined organic phases
were washed with water and dried over anhydrous sodium
sulphate. The solvent was distilled at reduced pressure to ob-
tain the crude product, which was purified by passing
through a column using silica gel (60–120 mesh size) and
petroleum ether – ethyl acetate (10:1) as an eluent to afford
pure product 4.
3H, C1-COCH3), 6.50–7.30 (m, 5H, C4-OC6H5), 7.86 (s, 1H,
C6-H), 13.40 (bs, 1H, C2-OH). MS (70 eV) m/z: 434 (M+,
8.9), 434 (M+, 7.7), 433 (49), 431 (48), 342 (15), 340 (100),
338 (92), 291 (12). Anal. calcd. for C14H10BrIO3: C 38.80,
H 2.31; found: C 38.70, H 2.40.
2-Hydroxy-3-iodo-4-phenoxypropiophenone (4e): IR (Nujol,
1
cm–1): 1635 (C=O). H NMR (CDCl3) δ: 0.80–0.96 (t, 3H,
C1-COCH2-CH3), 2.50–3.00 (q, 2H, C1-COCH2CH3), 6.50–
7.90 (m, 7H, C4-OC6H5, C5-H and C6-H). Anal. calcd. for
C15H13IO3: C 48.91, H 3.53; found: C 48.71, H 3.36.
2-Hydroxy-3-iodo-5-propionyl-4-phenoxypropiophenone (4f):
1
IR (Nujol, cm–1): 1630 (C=O). H NMR (CDCl3) δ: 0.70–
The physical data of the pure products are listed in Ta-
ble 1.
1.30 (t, 6H, C1- and C5-COCH2-CH3), 2.50–3.20 (q, 4H, C1-
and C5-COCH2CH3), 6.45–7.30 (m, 5H, C4-OC6H5), 8.25 (s,
© 1999 NRC Canada

Prakash et al.
1195
Acta, 28, 63 (1995); (f) P.J. Stang and V.V. Zhdankin. Chem.
Rev. 96, 1123 (1996).
1H, C6-H), 9.55 (bs, 1H, C2-OH). Anal. calcd. for
C18H17IO4: C 50.94, H 4.00; found: C 50.86, H 3.86.
2. (a) A. Varvoglis. The organic chemistry of polycoordinated io-
dine. VCH Publishers, New York. 1992; (b) G.F. Koser. In The
chemistry of halides, pseudo-halides, and azides. Suppl D2.
Edited by S. Patai and Z. Rapport. Wiley–Interscience,
Chichester. 1995. Chap. 21. p. 1173; (c) A. Varvoglis. Hypervalent
iodine in organic synthesis. Academic Press, New York. 1997.
3. R.M. Moriarty and O. Prakash. Adv. Heterocycl. Chem 69, 1
(1998).
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6. O. Prakash and S.P. Singh. Aldrichimica Acta, 27, 15 (1994).
7. R.M. Moriarty and O. Prakash. Acc. Chem. Res. 19, 244 (1988).
8. O. Prakash, S. Goyal, S.P. Singh, and R.M. Moriarty. Indian J.
Chem. Sect. B: Org. Chem. Incl. Med. Chem. 27B, 929 (1988).
9. R.M. Moriarty, O. Prakash, I. Prakash, and H.A. Musallam. J.
Chem. Soc. Chem. Commun. 1342 (1984).
10. O. Prakash, S. Goyal, S. Pahuja, and S.P. Singh. Synth.
Commun. 20, 1409 (1990).
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1891 (1993).
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2-Hydroxy-3-iodo-5-nitro-4-phenoxypropiophenone (4g): IR
1
(Nujol, cm–1): 3300 (OH), 1645 (C=O). H NMR (CDCl3)
δ: 1.17 (t, 3H, C1-COCH2-CH3), 2.95 (q, 2H, C1-
COCH2CH3), 6.54–7.30 (m, 5H, C4-OC6H5), 8.60 (s, IH,
C6-Ar-H). Exact Mass (70 eV) m/z calcd. for C15H12INO5:
413.00; found: 412.98. MS m/z: 412.98 (77.7), 383.94
(53.8), 336.94 (27.8), 319.97 (47.9), 286.7 (39.6), 215.97
(26.0), 193.04 (100.0), 152.4 (23.0), 94.04 (68.2), 77.04
(32.6).
5-Bromo-2-hydroxy-3-iodo-4-phenoxypropiophenone (4h):
IR (Nujol, cm–1): 3300 (OH), 1640 (C=O). 1H NMR
(CDCl3) δ: 0.95 (t, 3H, C1-COCH2CH3), 2.75 (q, 2H,
C1-COCH2CH3), 6.60–7.40 (m, 5H, C4-OC6H5), 7.98 (s, IH,
C6-Ar-H). Exact Mass (70 eV) m/z calcd. for C15H12BrIO3:
448.00; found: 447.90. MS m/z: 447.90 (74.6), 445.90
(77.1), 418.86 (99.9), 416.87 (100.0), 354.86 (52.3), 352.87
(54.8), 342.83 (25.9), 340.83 (25.6), 296.85(34.6), 294.86
(70.3), 292.85 (35.0), 291.97 (25.5), 290.97 (27.4), 289.97
(24.6), 243.98 (22.6), 216.93 (73.6), 214.94 (75.6), 77.03
(34.0).
14. (a) A.R. Katritzky and C.W. Ress. Comprehensive hetero-
cyclic chemistry. Vol. 4. Pergamon Press, Oxford. 1984.
p. 708; (b) R.S. Burden, M.S. Kemp, C.W. Whiltshire, and J.D
Owen. J. Chem. Soc. Perkin Trans. 1, 1445 (1984).
15. (a) T. Kappe, G. Korbuly, and W. Stadlbauer. Chem. Ber. 111,
3857 (1978); (b) M.V. Sargent and P.O. Stransky. J. Chem.
Soc. Perkin Trans. 1, 1605 (1982).
16. (a) R. Laschober and T. Kappe. Synthesis, 387 (1990);
(b) D.E. Ames and A. Opalko. Synthesis, 234 (1983).
17. B.C. Schardt and C.L. Hill. Inorg. Chem. 22, 1563 (1983).
18. U.K. Mallik and A.K. Mallik. Indian J. Chem. Sect. B: Org.
Chem. Incl. Med. Chem. 31B, 696 (1992); S. Spyroudis and P.
Tarantili. Tetrahedron, 50, 11541 (1994).
2-Hydroxy-3-iodo-4-phenoxydeoxybenzoin (4i): IR (Nujol, cm–1):
3300 (OH), 1645 (C=O). H NMR (CDCl3) δ: 4.14 (s, 2H,
1
C1-COCH2C6H5), 6.15 (d, 1H, C5-Ar-H), 6.90–7.70 (m,
11H, C1-COCH2C6H5, C4-OC6H5, C6-Ar-H). Exact Mass
(70 eV) m/z calcd.: 430.00; found: 431.00. MS m/z: 431
(4.44), 430 (19.61), 341 (5.10), 340 (37.98), 339 (100.0),
302 (0.9), 263 (5.83), 234 (2.05), 211 (16.31), 184 (16.64),
128 (14.74), 102 (3.33), 101 (1.19).
Acknowledgment
19. N.S. Narasimhan, I.S. Aidhen, and N.M Sunder. J. Indian
Chem. Soc. 66, 703 (1989).
20. S.R. Cooper. Org. Synth. Collect. Vol. III, 761 (1953).
21. M.P. Tanwar. Ph.D. Thesis, Kurukshetra University,
Kurukshetra, India. 1994. pp. 66–73.
22. (a) R.E. Omer and C.S. Hamilton. J. Am Chem. Soc. 642
(1937); (b) A. Bobik, G.M. Holder, and A.J. Ryan. J. Med.
Chem. 1194 (1977).
23. V.J. Dalvi and G.V. Jadhav. J. Indian Chem. Soc. 33, 440
(1956).
We are grateful to the Council of Scientific and Industrial
Research (New Delhi) for financial assistance and to the
Mass Spectrometry Facility, Department of Pharmaceutical
Chemistry, San Francisco, California, for the scanning high-
resolution mass spectra.
References
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© 1999 NRC Canada