Biomimetic synthesis of (.+-.)-crambines A, B, C1, and C2. Revision of the structure of crambines B and C1

Magnesium Chloride Hexahydrate Catalyzed One‐Pot Synthesis of 3,4‐Dihydropyrimidin‐2‐(1H)ones Under Solvent‐Free Conditions

“…[3] The simple and direct method for the synthesis of DHPMs reported by Biginelli in 1893 involves the one-pot condensation of aldehyde, b-keto ester, and urea under strongly acidic condition. [4] This method suffers from low yields, especially in the cases of aliphatic and some substituted aromatic aldehydes.…”

“…[4] This method suffers from low yields, especially in the cases of aliphatic and some substituted aromatic aldehydes. Recently, many improved procedures were reported for the preparation of DHPMs using Bi(OTf ) 3 , [5] ZrCl 4 , [6] InCl 3 , [7] LiClO 4 , [8] FeCl 3 . 6H 2 O or NiCl 2 .…”

“…6H 2 O, [9] p-TsOH, [10] LaCl 3 . 7H 2 O, [11] Bi(OTf) 3 , [12] KHSO 4 , [13] ionic liquids (BMImPF 6 and BMImBF 4 ), [14] Mn(OAc) 3 . 2H 2 O, [15] or TMSOTf [16] as the catalyst.…”

Efficient One-Pot Synthesis of 3,3-Dimethyl-diphenyl-2,4-dioxa-8,10-diazaspiro[5.5]undecane-1,5-dione-9-thione Derivatives

“…烷-1,5-二酮-9-硫酮系属螺杂双环衍生物, 是构成一些 含螺环结构天然化合物的结构单元 [1,2] . 由于在抗病毒、 抗肿瘤、降血压、临床麻醉表现出广泛生物或药理活 性 [3,4] , 已引起人们的极大关注.…”

Magnesium Chloride Hexahydrate Catalyzed One‐Pot Synthesis of 3,4‐Dihydropyrimidin‐2‐(1H)‐ones under Solvent‐Free Conditions.

“…[2] In addition, several marine alkaloids with interesting biological properties contain 3, 4-dihydropyrimidinone-5-carboxylate moiety. [3] The simple and direct method for the synthesis of DHPMs reported by Biginelli in 1893 involves the one-pot condensation of aldehyde, b-keto ester, and urea under strongly acidic condition. [4] This method suffers from low yields, especially in the cases of aliphatic and some substituted aromatic aldehydes.…”