PHOSPHORSUBSTITUIERTE N,N′-DIMETHYLTHIOHARNSTOFFVERBINDUNGEN. II. SYMMETRISCH BISPHOSPHORYLIERTE DERIVATE

Abstract

The symmetrical N,N′-diphosphorus(III)-substituted derivatives 2-4 were obtained in the reaction of N,N′-dimethyl thiourea, 1 with the appropriate phosphorus(III) chlorine compound in the presence of an HCl acceptor.

An X-ray structure analysis of compound 2 [C2/c, a = 1646.1 pm, b = 948.1 pm, c = 1731.4 pm, β = 115.86°, R = 0.036] shows that the molecule possesses crystallographic twofold symmetry along the C‒S bond. The nonbonding phosphorus-phosphorus distance is 290 pm.

In the reaction of the mono-Pr₂P(III)-substituted derivative of thiourea, 5 with further diisopropylchlorophosphine, the S-substituted isomer, 6 (see part I of this series) was formed initially. Subsequently, in a second step, compound 6, at −20°C, underwent transformation into N,N′-bis(di-isopropylamino)N,N′-dimethyl thiourea, 7, An attempt at the synthesis of the bis(di-tert.-butylphosphino)-derivative, 9 was unsuccessful.

Key Words:

• N,N′-dimethyl thiourea
• N-phosphorylation
• S-phosphorylation
• x-ray.