REARRANGEMENT OF 2-HYDROXYALKYL ESTERS OF

DIPHENYLTHIO- AND SELENOPHOSPHORIC ACIDS

O. N. N u r e t d i n o v a a n d B . A. A r b u z o v UDC 542.952.1:547.1 '118

As a continuation of studying the r e a r r a n g e m e n t of the S-2-hydroxyalkyl e s t e r s of phosphorus acids we studied the i somer i za t i on of the 2-hydroxyalkyl e s t e r s of diphenylthio- and - se lenophosphor ic acids. By analogy with the S-2-hydroxya lky l e s t e r s of d i - t e r t -bu ty l th iophosphor ic acid [1], we pos tu la ted that the r e - a r r a n g e m e n t of the S-2-hydroxya lky l e s t e r s of diphenylthiophosphoric acid will be difficult due to s t e r i c h indrance by the phenoxyl groups . I t p r o v e d that, in c o n t r a s t to the e s t e r s of d i - ter~-butyI thiophosphor ic acid, which do not r e a r r a n g e to the O - 2 - m e r c a p t o a l k y l e s t e r s , the i somer i za t i on of the S-2-hydroxyalkyl e s t e r s of diphenylthiophosphoric acid s tops at the step of fo rming the products with a thiaoxaphospholane ring.

A signal in the 40-45 ppm region ( re la t ive to 85% H3PO4) is usual ly obse rved in the 3ip NMR sp ec t ru m of the reac t ion p roduc t s of ox i ranes with diphenylthiophosphoric acid, which can be ass igned to the in te rmedia te r e a r r a n g e m e n t p roduc t s . P r e v i o u s l y , based on the 31p NMR s p e c t r a , a s i m i l a r p roduc t was obse rved during the i somer i za t i on of the S-2-hydroxyalkyl e s t e r s of dialkyl thiophosphoric ac ids , but with t ime the s ignal at 40 ppm d i sappea red and t he r e r em a i ned only the signal of the p roduc t with a 2 - m e r c a p t e a l k y l group in the region f r o m - 2 t e - 4 p p m [2]. In the ca se of the e s t e r s of diphenylthiophosphoric acid the 31p NMR s p e c t r u m r ema ins constant with t ime.

I t is p robab le that during the i s om er i za t i on of the S-2-hydroxya lky l e s t e r s of diphenylthiophosphoric acid the r e a r r a n g e m e n t p r o c e e d s with c lo su re of the thiaoxaphospholane r ing and the l ibera t ion ofphenol . Phenol does not r e a c t with 2 -oxo-2 -phenoxy- l ,3 ,2 - th i aoxaphospho lanes at ~ 20~ As a resu l t , the reac t ion of ox i ranes with diphenylthiophosphoric acid gives a m ix tu r e of 2 -oxo-2-phenoxy- l ,3 ,2 - th iaoxaphospho lane (I)-(III) and phenol, which a r e s epa ra t ed by dist i l lat ion:

O--CHR ~

(PhO)2FSOH + R~I-1C CHR 2 --~ (Ph0)~PSCHCH011 --~ PhOP / + PhOH \ o / o R1R~ o" ~S_C[HR 1

(I)--(III) R ~ = R2= H (I); RX= H, R~ = Me (II); It* = R~= Me (III).

Compomlds (I)-(s a r e hydro ly t iea l unstable and a r e decomposed by wa te r o r alcohols with des t ruc t ion of the thiaoxaphospholane r ing. S imi la r p roduc t s were obtained p rev ious ly by the vacuum dist i l lat ion of the S-2- hydroxyalkyl e s t e r s of dialkyl thiophosphoric acids [3]. 2 - O x o - 2 - i s o p r o p o x y - 4 , 5 - d i m e t h y l - l , 3 , 2 - t h i a o x a p h o s - pholane (IV) was obtained by this method in the p r e s e n t p a p e r

Me 0 0--CHMe 1 Distillation II/ ]

(i-Pr O)~FSCHCHOH /-PROP II ] o,I--O,~ mm ~, J

0 Me S--CHMe (iv)

+ i-Pr 01-]

When the mixed e s t e r s of e i ther ethylphenyl- o r i sopropylphenyl th iophosphor ic acid a re r eac ted with ox i ranes , the alp NMR s p e c t r u m of the reac t ion mix tu re has , bes ides a signal at 40 ppm, a signal in the region f r o m - 8 to - -1g ppm, which tes t i f i es to p r o g r e s s of the hydroxythiol r e a r r a n g e m e n t up to the step of fo rming the 2 - m e r c a p t o a l k y l e s t e r . When this mix tu re is dis t i l led, the f i r s t to dist i l l a re phenol and the other low- boiling p roduc t s , and then the thiaoxaphospholane

A. E. Arbuzov Inst i tute of Organic and Phys ica l Chemis t ry , Kazan Branch of the Academy of Sciences of the USSR. T r a n s l a t e d f r o m Izves t i ya Akademii Nauk SSSR, Seriya Khimicheskaya , No. 5,pp. 1130-1132, May, 1981. Original a r t i c l e submi t ted May 19, 1980.

890 0568-5230/81/3005-0890507.50 �9 1981 Plenum Publishing Corpora t ion

/-PRO \

PSOH -}- .MeHC CHMe

PhO / %/

i-PrO O--CHMe 20--30 ~ /

\PSCH--CtiOH ~ i-PrOP /II I [ 7so mm [1\ I

Ph0 0 Me Ne O S--CHMe (IV)

A dark-brown residue remains after distillation, whose main signal in the 31]? NMR spectrum (- i0 ppm) ap- parently corresponds to the acid i-PrO(PhO)PO2H.

The reaction of oxiranes with diphenylselenophosphorie acid proceeds in a similar manner to give selenaoxaphospholanes ((sap 32 pprn), which are stable only in solution (ether, benzene) and decompose when the solvent is removed with the deposition of elemental selenium:

Se--CH~,

PhOP/ ' C~K~

(PhO),PSeOH ~- MeHC CH, ~ (PhO)zPSeCH~CHMe " " iJ l il \ I

/ 0 OH 0 0--CHMe

A p p a r e n t l y , i t was f o r t h i s r e a s o n t ha t the f o r m a t i o n of s e l e n a o x a p h o s p h o i a n e s cou ld not be r e c o r d e d p r e v i o u s l y

[4].

EXPERIMENTAL

Reaction of Oxiranes with Diphenylthiophosphoric Acid. To an ether solution of diphenylthiophosphoric acid was carefully added {or by bubbling in the case of ethylene oxide) an excess of the oxirane (mole ratio = 1:1.2), after which the mixture was reflu_xed, cooled, the solvent was distilled off at I0 torr, and the residue was distilled at a higher vacuum. In all of the experiments the phenol distilled in the range 40-80~ (0.15 ram). Then the 2-oxo-2-phenoxy-l,3,2-thiaoxaphospholanes distilled. (i) bp 136~ (0.09 ram); d420 1.3682; nD 2~ 1.5688. Fomnd: C 45.00; H 4.18; P 14.13%. CsHg?3PS. Calculated: C 44.44; H 4.16; P 14.35%. 6aP + 42 ppm. (H), bp 145-150~ (0.08 ram); d42~ 1.3011; nD 2~ 1.0560. Found: C 47.22; H 4.60; P 13.08%. CsHIiO3PS. Calculated: C 46.95; H 4.78; P 1 3.47%. (531p + 41 ppm. {HI), bp 134-137 ~ (0.08 ram). Found: P 12.37; S 12.72~c. CIoHI303PS. Calculated: P 12.70; S 13.11%. (sap 40 ppm.

2- Oxo-2-isopropoxy-4,5-dimethyl- 1,3,2-thiaoxaphospholane (IV). a) The distillation of O,O-dlisopropyl S-l-methyl-2-hydroxypropyl thiophosphate, obtained as described in [3], gave (IV) with bp 85-86~ (0.I ram); d42~ 1.1710; nD2~ Found: C 40.36; H 7.10; P 15.00%. CTHisO3PS. Calculated: C 40.00; H 7.114; P14.76%. (53ip + 38 p p m .

b) The reaction of isopropylphenylthiophosphoric acid with 2,3-butylene oxide gave (IV) in ~,60% yield, bp 97-98~ (0.15 mm); d420 1.1720; nD 20 1.4805. Found: P 14.42%. CTHI503PS. Calculated: P 14.7(~%. 631P 38 p p m . *

C O N C L U S I O N S

Diphenylthio- and -selenophosphoric acids react with oxiranes to give 2-oxo-2-phenoxy-!,3,2-thia- or -selenaoxaphospholanes. Isopropylphenylthiophosphoric acid reacts with oxiranes to give a mixture of phosphorus-containing compounds, in which the thiaoxaphospholanes with an alkoxyl substituent on the phosphorus atom predominate.

1.

2. 3. 4.

LITERATURE CITED

O. N. Nuretdinova and F. F. Guseva, Izv. Akad. Naak SSSR, Ser. Khim., 197__~9~ 1901. O. N. Nuretdinova and F. F. Guseva, !zv. Akad. Nauk SSSR, Ser. Khim., 197____88, 2142. O. N. Nuretdinova, F. F. Guseva, and B. A. Arbuzov, Izv. Akad. Nauk SSSR, Set. Khim., 19___j7_6_6 , 2625. I. A. Nuretdinov, N. A. Buina, E. V. Bayandina, O. N. Nuretdinova, F. G. Sibgatullina, and D. N. Sadkova, Abstracts of Papers Delivered at International Conference on Phosphorus Chemistry, Halle, Germany (1979), p. 319.

891