7-Benzyl-3- tert -butyl-1-phenyl-6,7-dihydro-1 H ,4 H- pyrazolo[3,4- d ][1,3]oxazine, C 22 H 25 N 3 O, ( I), 和 3-叔丁基-7-(4-甲基苄基)-1-苯基-6,7-二氢-1 H ,4 H-吡唑并[3,4- d ][1,3]恶嗪, C 23 H 27 N 3 O (II) 在空间群P 2 1中同晶,分子通过 C-H...O 氢键连接成链。在每个 3-叔丁基-7-(4-甲氧基苄基)-1-苯基-6,7-二氢-1 H ,4H- pyrazolo[3,4- d ][1,3]oxazine, C 23 H 27 N 3 O 2 , (III),其泡孔尺寸与 (I) 和 (II) 非常相似,也在P 中2 1 , 和 3-叔丁基-1-苯基-7-[4-(三氟甲基)苄基]-6,7-二氢-1 H ,4 H-吡唑并[3
An efficient and three-step procedure for the synthesis of novel 6,7-dihydro-1H,4H-pyrazolo[3,4-d][1,3]oxazine derivatives in good to excellent yields by treatment of pyrazolamines with aqueous formaldehyde in the presence of acetic acid is provided. The reactions proceeded through an intramolecular etherification process by dehydration of a 1,5-diol intermediate formed in the course of the reaction