PHOSPHORUS, SULFUR, AND SILICON
3
procured from S.D. Fine Chem. Ltd., Boisar, India, was dried synthetic and analytical data of all the compounds (3a–b, 5a–b)
over anhydrous calcium chloride followed by sodium wire and provided.
distilled before use. The other solvents were obtained from S.D.
Fine Chem. Ltd., Boisar, India and Qualigens Fine Chemicals,
6-(2-Chloroethyl)-12-oxo-dibenzo[d,g][1,3,2]
Mumbai, India and were used after purifying by the established
dioxaphosphocin 6-oxide (3a)
Phosphorus oxychloride was procured from Ubichem Ltd., Yield: 58%. m.p: 152–154 °C. IR data (KBr): 1211 (P = O), [(P)-
1
England, whereas, Phosphorus trichloride was procured from O-Caromatic]: 993 (P-O), 1149 (O-C), 1627 (C = O) cm−1. H
Spectrochem, Mumbai, India and used without further purifica- NMR (CDCl3): δ 6.80–7.52 (m, 8H), 2.03–2.23 (m, 2H, PCH2),
tion. Triethylamine obtained from S.D.Fine Chem. Ltd., Boisar, 3.33–3.50 (m, 2H, CH2Cl). 13C NMR (CDCl3): δ 132.6 (C-
India was dried over potassium hydroxide pellets and distilled. 1&11), 130.2 (C-2&10), 133.9 (C-3&9), 121.9 (C-4&8), 146.6
2,2ꢀ-Dihydroxybenzophenone and 2,2ꢀ-dihydroxybiphenol were (d, 2JPOC = 9.5 Hz, C4a&7a,), 125.7 (C-11a&12a), 199.9 (C-12),
purchased from Sigma-Aldrich Chemical Company, Inc. USA 30.5 (d, 1JPC = 140.3 Hz, PCH2), 36.7 (CH2Cl). 31P NMR (85%
and used without further purification.
H3PO4): 42.7 ppm. Anal. Calcd. for C15H12O4PCl: C 55.84, H
3.75; Found: C 55.69, H 3.62
Preparation of 2-chloroethylphosphonic dichloride (2a)
6-Bis(2-chloroethyl)amino-12-oxo-dibenzo[d,g][1,3,2]
dioxaphosphocin 6-oxide (3b)
A mixture of phosphorus trichloride (34.4 g, 0.25 mole),
anhydrous aluminum chloride (33.4 g, 0.25 mol) and 1,2-
dichloroethane (24.8 g, 0.25 mole) was refluxed in a three-
necked round bottomed flask with stirring till all the AlCl3 dis-
solved. After cooling to −5 to 0 °C, 300 mL of methylene chlo-
ride was added slowly from a dropping funnel with stirring
and then water (45.0 g, 2.5 mol) was added dropwise at −10°C
with vigorous stirring. After removal of aluminum salts, the sol-
vent was distilled off and the residual liquid was removed under
reduced pressure, (bp 100 °C / 20 mm), to give a colorless liquid
Yield: 62%. m.p: 128–130 °C. IR data (KBr): 1290 (P =
O), [(P)-O-Caromatic]: 945 (P-O), 1207 (O-C), 1636 (C = O)
cm−1 1H NMR (CDCl3): δ 7.27–8.10 (m, 8H), 3.18–3.29
.
(m, 4H, N(CH2)2), 3.53–3.58 (m, 4H, (CH2Cl)2). 13C NMR
(CDCl3): δ 133.1 (C-1&11), 132.1 (C-2&10), 134.9 (C-3&9),
3
2
124.3 (d, JPOCC = 2.9 Hz, C-4&8), 148.2 (d, JPOC = 8.8 Hz,
C4a&7a,), 127.1 (C-11a&12a), 188.1 (C-12), 42.0 (N(CH2)2),
50.4 (d, 3JPN-2C = 2.3 Hz, (-CH2Cl)2). 31P NMR (85% H3PO4):
20.5 ppm. Anal. Calcd. for C17H16NO4PCl2: C 51.02, H 4.03;
Found: C 50.88, H 3.97. EI-MS (70 eV), m/z (%): 399 (1.2, M+.),
366 (1.2), 364 (2.5), 352 (32.5), 350 (100), 288 (13.7), 259 (15),
215 (3.7), 198 (3.7), 168 (12.5), 151 (7.5), 139 (13.7), 124 (21.2),
109 (8.7), 92 (18.7).
Bis(2-chloroethyl)phosphoramidic dichloride (2b)
Triethylamine (20.2 g, 0.2 mole) in dry toluene (75 mL)
was added dropwise to a stirred suspension of bis(2-
chloroethyl)amine hydrochloride (17.8 g, 0.1 mole) and
phosphorus oxychloride (15.3 g, 0.1 mole) in dry toluene
(150 mL) under inert atmosphere in a three-necked round
bottomed flask (500 mL), equipped with reflux condenser. After
completion of the addition, the reaction mixture warmed to
reflux, filtered and the filtrate was subjected to flash evaporation.
The residue obtained was purified by vacuum distillation under
reduced pressure to yield 19.5 g (75%) of compound 2a, bp
6-(2-Chloroethyl) dibenzo[d,f][1,3,2]-dioxaphosphepin
6-oxide (5a)
Yield: 62%. m.p: 97–99 °C. IR data (KBr): 1299 (P = O) cm−1
.
1H NMR (CDCl3): δ 7.26–7.56 (m, 8H), 2.53–2.64 (m, 2H,
PCH2), 3.85–3.94 (m, 2H, CH2Cl). 13C NMR (CDCl33): δ 130.2
(C-1&11), 126.6 (C-2&10), 130.3 (C-3&9), 121.4 (d, JPOCC
=
2
3.4 Hz, C-4&8), 128.6 (C-12&13), 147.4 (d, JPOC = 9.2 Hz,
C4a&7a,), 28.0 (d, 1JPC = 131.7 Hz, PCH2), 35.7 (CH2Cl). 31
P
NMR (85% H3PO4): 25.3 ppm. Anal. Calcd. for C14H12O3PCl:
C 57.06, H 4.10; Found: C 56.92, H 3.99.
General procedure for cyclocondensation reactions (3a–b
and 5a–b)
6-Bis(2-chloroethyl)amino
dibenzo[d,f]-[1,3,2]dioxaphosphepin 6-oxide (5b)
A solution of dichloride 2a–b (0.01 moles) in dry toluene
(20 mL) was added over a period of 20 min to a stirred solution Yield: 68%. m.p: 98–100 °C. IR data (KBr): 1312 (P = O) cm−1
.
of 2,2ꢀ-dihydroxybenzophenone, 1 or 2,2ꢀ-dihydroxybiphenol, 1H NMR (CDCl3): δ 7.33–7.57 (m, 8H), 3.36–3.45 (m, 4H,
4 (0.01 moles) and triethylamine (0.02 moles) in dry toluene N(CH2)2), 3.58–3.60 (m, 4H, (CH2Cl)2). 13C NMR (CDCl3):
(50 mL) at 0 °C. After completion of the addition, temperature δ 130.0 (C-1&11), 126.5 (C-2&10), 130.1 (C-3&9), 121.6 (d,
of the reaction mixture was raised to 45–50 °C and stirred for 5– 3JPOCC = 4.6 Hz, C-4&8), 127.9 (C-12&13), 148.0 (d, JPOC
=
2
6 h. The progress of the reaction was monitored by TLC analysis 9.1 Hz, C4a&7a,), 41.9 (N(CH2)2), 49.3 (d, 3JPN-2C = 3.4 Hz, (-
(EtOAc-Hex, 1:3). The precipitated triethylamine hydrochloride CH2Cl)2). 31P NMR (85% H3PO4): 12.3 ppm. Anal. Calcd. for
was filtered and then filtrate was evaporated in a rotaevapora- C16H16NO3PCl2: C 51.63, H 4.33; Found: C 51.48, H 4.26. EI-
tor under vacuum. The residue obtained was washed with water MS (70 eV), m/z (%): 399 (1.2, M+.), 366 (1.2), 364 (2.5), 352
followed by chilled 2-propanol. Colorless crystals were obtained (32.5), 350 (100), 288 (13.7), 259 (15), 215 (3.7), 198 (3.7), 168
by recrystallization of the crude product from 2-propanol. The (12.5), 151 (7.5), 139 (13.7), 124 (21.2), 109 (8.7), 92 (18.7).