Abstract
In the pursuit of biologically active compounds we required as a key intermediate 2,3-dihydro- 1,3-benzoxaz-bones having a halomethylene moiety at C(2), i.e. 3 (R2 = H or alkyl, R3 = CH2X). The standard procedure for the preparation of this class of compounds is the condensation of salicylamide derivatives 1 with the proper aldehyde1-5 and ketone5,6. Usually, hydrochloric acid or sulphuric acid is used as catalyst and the water formed is cocornmittently removed using a dehydrating agent or by azeotropic destillation7. These procedures did not serve our purpose as the required α-substituted aldehyde or ketone as such is unstable under the conditions employed. Here we report that employment of acetals and ketals 2 affords the desired compound 3; yields are appreciable when the proper reaction conditions are used.