2,2 -Bibenzoxazole

These two compounds are readily available by condensation of o-amino (thio)phenol with oxalic acid derivatives. 2,2 -Bibenzoxazole (80) was first prepared more than 70 years ago, but was incorrectly formulated as a benzoxazinobenzoxazine (25HCA16). It is readily prepared by oxidation. 

The X-ray of 2,2 -bibenzoxazole showed that the two rings are coplanar with an anti conformation (98AX(C)668) planar conformation and disorder resulting from the occurrence of cis and trans orientation were observed by X-ray of lH-3-trifluoromethyl-5-(2-thienyl)-pyrazole (OOJMS (526)59). l,l -Disubstituted 4,4 -bi-lH-l,2,3-triazols have been prepared by a click reaction. X-rays showed that the two triazole rings are perfectly coplanar (07EJIC4597). As expected, substitution in ortho positions of the pivot bond drastically changed the stereochemistry in this bi-heterocydic series. 

Tetrahydro-2,2 -bibenzoxazole, T-00053 Phosphorodithioic acid 0,0-bis(2-methylallyl) ester, P-00216 Phosphorodithioic acid 0,0-bis(2-methylallyl) ester. K salt, in P-00216... 

Geometry-optimized CNDO/2 molecular orbital calculations are carried out on poly(5,5 -bibenzoxazole-2,2 -diyl-1,4-phenylene)- and poly(2,5-benzoxazole)-model compounds to determine conformational energies as a function of rotation about each type of rotationable bond within the repeat units. 

Acetylene-Terminated Fluorocarbon Ether Bibenzoxazole Oligomers... 

Figure 2. Differential scanning calorimetry curve of fluorocarbon ether bibenzoxazole oligomer.

Bibenzoxazole derivative from cultures of Strepto-myces morookaensis, C22H14NJO5, Mr 386.36, needles, mp. 217-219°C. UK-I is cytotoxic and shows activity against certain tumor cell lines. 

Derivatives of 2-substituted perfluoroalkyl-5-oxazolecarboxylic acid have been found effective in reducing herbicidal injury to crop plants caused by thio-carbamate and acetanilide herbicides, and especially in reducing herbicidal injury to rice, sorghum or wheat corps, especially rice and sorghum, caused by triallate, alachlor and butachlor herbicides [73], 2,2 -Bis(heptafluoropro pyl)-5,5 - [74] and -6,6 -bibenzoxazoles [75] are suitable for use as antiplasticizers. 

---