Synthesis And Nucleophilic Reactions Of Carbamyl Silane

We have synthesized carbamyl silane 7, and studied its reactionwith the oxime ether, chloride,α-carbonyl amide, through which thesteric and electronic effects on the reaction rate has beendiscussed.At first we proposed a simple, convenient, and efficientsynthetic route of the oxime ether. The method is based onacetophenone as the substrate to obtain the acetophenoneoxime ,with which sodium hydroxide reacted to generate theacetophenone oxime sodium salt, then the salt reacted withhalogenated hydrocarbons synthesized a series of oxime ether,acetophenone - o - ethyl oxime ether 28, acetophenone - o - phenyloxime ether 29, acetophenone - o - o - fluorophenyl oxime ether 30,acetophenone - o - p - fluorophenyl oxime ether 31, acetophenone - o- m - methoxy - phenyl oxime ether 32, acetophenone - o - o -chlorophenyl oxime ether 33, acetophenone - o - m - chlorophenyloxime ether 34, acetophenone - o - p - chlorophenyl oxime ether 35,acetophenone - o - 2, 4 - dichloro - phenyl oxime ether 36. Then theoxime ethers react with the carbamyl silane 7 of N, N-dimethyl -(trimethylsilyl) formamide, but we found that did not work. We getthe same result by adding BF3·Et2O, AlCl3, CuCl, TBAT as catalyst,setting the 100℃. We suspected that it may be a result of the inactivity of carbamoylsilane.Carbamoylsilane 7 reacts with n-butyl chloride, tert-butylchloride, isobutyl chloride, benzoyl chloride, ring hexyl chloriderespectively, to generate N, N - dimethyl -α- carbonyl glutaramicmamide 37, N, N - dimethyl -α- carbonyl new glutaramic mamide 38,N, N - dimethyα- carbonyl new has mamide 39, N, N - dimethyl -α-carbonyl benzoyl acetamide 40, N, N - dimethyl -α- carbonylcyclohexyl acetmamide 41, experiments show that the sterichindrance have effects on the rate of such reactions .The greaterthe steric hindrance is, the slower the rate. Carbamoylsilane 7 reactwith o - chloro - benzoyl chloride, inter - methoxy benzoyl chloride,nitrobenzoyl chloride, cinnamon chloride, which are of the electronwithdrawing groups.And respectively generate N, N - dimethyl -α-carbonyl - o - chlorophenyl acetmamide 42, N, N - dimethyl -α-carbonyl - p - nitro benzoyl acetmamide 43, N, N - dimethyl -α-carbonyl - m - methoxy benzoyl acetmamide 44, N, N - dimethyl -α-carbonyl benzoyl butene amide 45. The experiment found that thechloride phenyl with electron withdrawing groups activates thereaction substrate, and accelerates the reaction rate.Carbamoylsilane 7 reacts with benzoylchloride, which has aelectron donating group, to generate N, N - dimethyl -α- carbonyl - p- methyl benzoyl acetmamide 46, the electron - donating effectlenthened the reaction time. Carbamoylsilane 7 reacts with 2-furylchloride to get the N, N - dimethyl -α- carbonyl - ( 2 - furoyl )acetmamide 47.Carbamoylsilane 7 reacts withα- carbonyl amide in anhydrousoxygen - free conditions , 105°C, toluene as solvent,then the derivatives ofα- hydroxy Malonamide are acquired.On this basis,they proposed a possible mechanism of this reaction.Carbamoylsilane 7 reacts withα- carbonyl amide 42, 43, 44, 45 ,respectively, to generate N, N, N’, N’ - tetramethyl - 2 - o -chlorophenyl - 2 - hydroxyl malonamide 51, N, N, N’, N’ - tetramethyl- 2 - nitrophenyl - 2 - trime thylsilyloxy malonamide 52, N, N, N’, N’-tetramethyl - 2 - m - methoxy - phenyl - 2 - trimethylsilyloxymalonamide 54, N, N, N’, N’ - tetramethyl - 2–styrene - 2–hydroxylmalonamide 55. It was found that electron withdrawing groupsenhance the electropositivity of the carbonyl carbon, and activatethe substrate, and accelerate the reaction rate. Carbamyl silane 7reacts withα- carbonyl amide 46 containing the electron-donatinggroup to generate N, N, N’, N’–tetramethyl - 2 - methyl - phenyl - 2 -trimethyl silyloxy malonamide 53. The experiment showed that theelectron-donating groups reduce the electronpositivitity of thecarbonyl carbon, slower the reaction rate. Carbamoylsilane 7 isreacs with theα- carbonyl amide 37, 38, 39, 40 to obtain the N , N, N’,N’ - methyl - 2 - propyl - 2 - hydroxy malonamide 48, N, N, N’, N’ -tetramethyl - 2 - isopropyl - 2 - hydroxy malonamide 49, N, N, N’, N’ -tetramethyl - 2 - phenyl - 2 - hydroxyl malonamide 50, N, N, N’, N’ -tetramethyl - 2 - cyclohexyl - 2 - trimethylsilyloxy malonamide 56.The experiments show that the greater the steric hindrance is, themore difficultly the reaction carried. N, N, N’, N’ - tetramethyl - 2–furyl - 2 - hydroxy malonamide 57 is synthesized bycarbamoylsilane 7 withα- carbonyl amide 47 with heterocyclic.Compounds 52, 53, 54 are derivatives of alpha-trimethylsilyloxymalonamide. But compounds 48, 49, 50, 51, 55, 56, 57 are derivatives of hydroxy malonic amide .We analysised the reasonmay be that the trimethylsilyloxy has been converted to thehydroxyl by the effect of H in the solvent.