Studies on B-Halogenated Pyrazaboles.
Abstract
A series of 4,4,8,8-tetrahalopyrazaboles of the type X2B(mu-pz*)2BX2 (Hpz*= C-substituted pyrazole, X = Cl,Br) has been prepared by reaction of the corresponding B-tetrahydro derivatives with elemental halogen. The reaction of (C2H5)2O.BF3 with pyrazabole, H2B(mu-pz)2BH2, has been used for the preparation of both F2B(mu-pz)2BF2 and F2B(mu-pz)2BF2 and F2B(mu-pz)2BH2 (Hpz = pyrazole). The later was chlorinated to yield the unsymmetrical B-tetrahalopyrazabole Cl2B(mu-pz)2BF2. 4,8-Dihalopyraboles, XRB(mu-pz)2BXR, have been obtained (as isomer mixtures) by the reaction of RBX2 with (CH3)3Si(pz). In addition, the 4,4-dihalopyrazaboles X2B(mu-pz)2B(C6H5)2 with X = F or Cl have been prepared. Representative reactions of the cited types of B-halogenated pyrazaboles, e.g, with organometallics, carboxylic acid anhydrides, and alcohols are described. New types of B-substituted pyrazaboles include the first example of a pyrabole where each boron atom is bonded to two different terminal hydrocarbon substituents. The structures of three species have been determined.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1987
- Accession Number
- ADA176441
Entities
People
- C. M. Clarke
- E. Hanecker
- J. F. Mariategui
- Kurt S. Niedenzu
- M. K. Das
Organizations
- University of Kentucky