Reaction of carbodiimides with phosphorothioic, phosphorodithioic, and phosphoroselenoic acids: products, intermediates, and steps

Abstract

The reaction of the title acids with dicyclohexylcarbodiimide (DCC) used in a 2:1 ratio was found to give a complex mixture of products consisting of thio(seleno)pyrophosphates, thiolo(selenolo)phosphates, thiono(selenono)phosphates, dicyclohexylthiourea (DCTU), and a polymeric alkyl metaphosphate. When both reaction components are mixed in a 1:1 ratio, ,ZV-phosphoryl-jVhZV-dicyclohexylthio(seleno)ureas (B) were formed. The formation of equimolar adducts (B) was also observed with other dialkyl-and diarylcarbodiimides. The spectral properties (especially the value of 123 4t7p_H) and reactivity of these adducts are strongly dependent on their conformation. The distinct conformational differences between the adducts B derived from DCC and diisopropylcarbodiimide (DiPC) and those obtained from dibenzylcarbodiimide (DBC) and diarylcarbodiimides were revealed by X-ray analysis of the selected IV-phosphorylthioureas. By means of low-temperature FT 31P NMR spectra it was demonstrated that the adducts (B) arise from the first formed unstable S(Se) -phosphorylisothio(seleno)ureas (A) as a result of S(Se)-*-N phosphoryl migration. The differences in ability of the phosphoryl group to undergo S(Se)-*N and -*-N 1,3-shifts are briefly described. iV-Phosphorylthio(seleno)ureas (B) obtained from DCC and DiPC, in contrast to those prepared from DBC and diarylcarbodiimides, reacted with a second thio(seleno)acid molecule. Crossover experimente and the use of , -diethyl phosphorothioate containing ^-labeled sulfur showed that the adducts (B) are in equilibrium with their unstable isomers (A), the latter being active phosphorylating agents. The formation of the final reaction products was rationalized in terms of the threedirectional attack of the thioacid anion at the phosphorus, alkoxy carbon, and central carbon atoms of the protonated adduct (A).

Structure et conformation du thioxo-2 1,3-benzoxazolyl-3 phosphonothioate de diphényle,analogue d'une forme 'N-phosphobiotine'

“…Nous avons synth&is6 le compos6 (1), nomm~ dans le titre, comme mod61e; c'est un thiocarbamate cyclique accol~ hun groupe benzo pour forcer le cycle oxazole dans une conformation plane comme dans la biotine (Chen, Parthasarathy & De Tita, 1976); le choix d'un carbamate cyclique h 6t6 fait pour 6viter la N-disubstitution ce qui aurait &~ le cas d'un cycle ur~'/do; le remplacement du carbonyle de l'ur6e par un fonction thione doit permettre de comparer cette structure d'autres tr6s proches d6j~t publi6es par nous-m~mes, ou que l'on trouve dans la litt~rature (Blonski, Gasc, Hegarty, Kla6b6 & P6ri~, 1984;Mikolajczyk, Kielbasinski & Basinsky, 1984). (1) 10370 (1) 1575 (2) 8437 (2) 3,79 C (2) 9844 (1) 1776 (3) 7458 (3) 3,41 N (3) 9576 (1) 342 (2) 7138 (2) 3,03 C (4) 9956 (1) -785 (3) 7934 (2) 2,84 C (5) 10438 (1) 19 (3) 8722 (2) 3,23 C (6) 10915 (1) --666 (3) 9658 (3) 3,97 C (7) 10891 (1 8895 (0) 155 (1) 5948 (1) 2,97 S (12) 8910 (0) 728 (1) 4101 (1) 4,09 O (13) 8749 (1) -1593 (2) 6198 (2) 3,97 C (14) 8497 (1) -2629 (3) 5129 (2) 3,53 C (15) 8893 (2) -3542 (4) 4559 …”

“…1363 (5) 5665 (4) 5,66 C (25) 6903 (2) 2114 (5) 4897 (4) 5,68 C (26) 7550 ( Cette distance est ~ comparer h celle d'un homologue acyclique de la littbrature (Mikolajczyk, Kielbasinski & Basinsky, 1984). I1 s'agit d'une thiour+e substitu6e analogue ~ (1) dont la distance S...P est de 3,73 ,~ et pour laquelle la migration du groupe phosphoryle, de l'atome d'azote ~ l'atome de soufre, est r+versible.…”