α-MAP偶氮物的合成

以α-4-BMA{(3S,4S)-3-[(R)-1-(叔丁基二甲基硅氧基)乙基]-4-[(S)-1-甲酰乙基]-2-氮杂环丁酮}为起始原料,通过缩合、水解等反应合成了β-MAP(1β-甲基碳青霉烯双环母核)偶氮物的异构体杂质——α-MAP偶氮物,其结构经1H NMR和IR核磁确证,并建立了相应的分析方法。     

海兔毒素10关键合成子Dap的立体专一性合成

以N-丙酰基-(3R,4S)-3-甲基-4-苯基-2-羰基噁唑啉与N-(叔丁氧羰基)-S-脯氨醛为原料,经羟醛缩合反应合成了高立体专一性、具有三个手性中心的(4S,5S,2'R,3'R,2"S)-3-[3'-(N-叔丁氧羰基-2"-吡咯烷基)-3'-羟基-2'-甲基丙基)]-4-甲基-5-苯基-2-羰基噁唑烷酮(6);6脱去手性辅基,甲基化3'-羟基合成了抗肿瘤活性肽海兔毒索10的关键合成子--(2S,3S,2's)-3-(N-叔丁氧羰基-2'-吡咯烷基)-3-甲氧基-2-甲酸丙酸,其结构经1H NMR,13C NMR,m和MS表征.     

N~6,N~6-二(叔丁氧羰基)-2',3'-O-异丙叉腺苷的合成

以腺苷(2)为原料,经丙酮叉保护2',3'-位羟基得2',3'-O-异丙叉腺苷(3);3经叔丁基二甲硅氯保护5'-羟基得5'-O-叔丁二甲基硅基-2',3'-O-异丙叉腺苷(4);4经二碳酸二叔丁酯保护氨基得到N~6,N~6-二(叔丁氧羰基)-2',3'-O-异丙叉基-5'-O-叔丁二甲基硅基腺苷(5);5用四丁基氟化铵脱去叔丁二甲基硅基合成了新化合物N`6,N~6-二(叔丁氧羰基)-2',3'-O-异丙叉腺苷,总收率54.3%,其结构经~1H NMR,~(13)C NMR,IR和HR-MS表征.     

新型2-(吡咯烷-3-基)-噁唑衍生物的合成

根据亚结构链接法,以氯甲基三甲基硅烷和苄胺为原料,依次经酯化、缩合、环合、水解、成盐等12步反应制得5个新型的(4-甲基氨基甲酰基-2-吡咯烷-5-甲基噁唑) 胺基甲酸叔丁酯衍生物(15a~15e); 15a与醛(酮)或乙酰氯反应,合成了4个新型的5-胺基甲基-2-(1-甲基-吡咯烷)-噁唑-N-甲基甲酰胺盐酸盐衍生物,其结构经¹H NMR和ESI-MS表征。     

比阿陪南双环母核的合成

从水杨酰胺出发,通过环合、酰化、Reformatsky反应、取代和Dieckmann环化反应,合成了碳青霉烯类抗生素比阿陪南的关键中间体--比阿陪南双环母核{(4R,5R,6S)-6-[(R)-1-叔丁基二甲基硅氧乙基]-3-二苯基磷酰氧基4-甲基-7-氧代-1-氮杂双环-[3.2.0]庚-2-烯-2-羧酸烯丙酯},总收率43.1%,其结构经1H NMR确证.     

利用Reformatsky反应合成1-β-碳氢霉烯类抗生素中间体

以(2R)-3-[(3S,4R)-1-(叔丁基二甲基硅氧基)乙基]-4-乙酰氧基氮杂环丁-2-酮为母体,2-溴乙(丙)酸酯或2-溴丙酰胺为亲核试剂,通过Reformatsky反应合成了一系列新型的1-β-碳氢霉烯类抗生素中间体——3-{(2R)-2-[(3S,4R)-1-(叔丁基二甲基硅氧基)乙基]氮杂环丁-2-酮-4-基}乙(丙)酸酯(3a～3d)和3-{(2R)-2-[(3S,4R)-1-(叔丁基二甲基硅氧基)乙基]氮杂环丁-2-酮-4-基}-N,N-二取代丙酰胺(3e,3i和3k),其结构经1H NMR和13C NMR表征,其中3a～3e和3i未见文献报道。     

合成(3R,4R)-3-[(1'R)-叔丁基二甲基硅氧乙基]-4-乙酰氧基-2-氮杂环丁酮的新方法

(3R,4R)-3-[(1'R)-叔丁基二甲基硅氧乙基]-4'-乙酰氧基-1-对甲氧基苯基-2-氮杂环丁酮依次经铋酸钠/浓硫酸体系氧化和亚硫酸氢钠还原,合成了培南类药物的重要中间体——(3R,4R)-3-[(1'R)-叔丁基二甲基硅氧乙基]-4-乙酰氧基-2-氮杂环丁酮(1),收率62%,纯度98%,其结构经1H NMR,IR和EI-MS表征。     

（2R，4S）-N-叔丁酰基-4-氨基-2-四氢吡咯甲酸甲酯的合成

以(2R,4S)-4-羟基-2-四氢吡咯甲酸为起始原料,经甲酰化,酰化引入叔丁氧羰基,手性反应,甲磺酰化,叠氮化及三苯基膦还原等7步反应合成了(2R,4S)-N-叔丁酰基-4-氨基-2-四氢吡咯甲酸甲酯(总收率29%),其结构经1H NMR和LC-MS表征.     

手性相转移催化剂的合成及其在氨基酸烷基化反应中的应用

以2-叔丁基-5-甲基苯酚为原料,经4步反应制得2,2'-二甲基-3,3'-取代基-4,4'-二甲氧基-5,5'-二叔丁基-1,1'-联苯(6a~6g);6经溴化反应制得2,2'-二溴甲基-3,3'-取代基-4,4'-二甲氧基-5,5'-二叔丁基-1,1'-联苯(7a~7g);7与(R)-(+)-N-甲基-1-(1-萘基)乙基胺经环合反应合成了7种具有联苯结构的手性相转移催化剂(9a~9g)。6f,6g,7f,7g,9f和9g为新化合物,其结构经1H NMR,13C NMR和MS表征。以N-二苯基亚甲基甘氨酸叔丁酯的不对称烷基化为探针反应,考察了9a~9g的催化活性。结果表明:在催化剂用量为1mol%时,9g的催化性能最好,产率和对映选择性分别为80%和70%。     

(R)-2-甲基半胱氨酸盐酸盐的合成方法改进

以L-半胱氨酸甲酯盐酸盐为起始原料,经4步反应合成了(R)-2-甲基半胱氨酸盐酸盐.在关键中间体(2R, 4R)-2-叔丁基-3-甲酰基-4-甲基-1,3-噻唑烷-4-甲酸甲酯(4)的合成中,采用Self-regeneration of stereocenters原理,用六甲基二硅胺钠取代文献方法中的二异丙基胺基锂,4的收率由文献的56%提高至90%.化合物的结构经1H NMR和MS表征.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.