Photochemistry of 2,2,4,4-Tetramethyl-3-thietan-1-ylidene: A Heterocyclic Carbene with an Unusually Short Lifetime and Evidence for a Nonclassical Structure
作者:John R. Snoonian、Matthew S. Platz
DOI:10.1021/jp0016840
日期:2001.3.1
Laser flash (308 nm) and steady-state photolysis (300 nm) of Δ3-1,3,4-oxadiazoline (3) produces a transient that can be trapped with pyridine to give an adduct with λmax = 350 nm, attributed to ylide 10. Laser flashphotolysis (LFP) studies of the ylide indicate that the value of kpyrτ (where kpyr is the absolute rate constant of carbene reaction with pyridine and τ is the carbene lifetime) of the
Reactions of cyclic disulfides with carbenes; desulfurization and insertion
作者:Wataru Ando、Yorio Kumamoto、Toshikazu Takata
DOI:10.1016/s0040-4039(00)98899-3
日期:1985.1
several cyclic disulfides with carbenes generated by catalytic and photochemical decompositions of diazo compounds have been studied. Carbenes reacted with cyclic disulfides yielding 1,3-dithiane quantitatively as S-S insertion reaction, while the selective desulfurization results in the reaction of disulfides with bulky substituents. The carbene reaction is sensitive to bulkiness of disulfides.
Alpha-L-aspartyl-D-phenylglycine esters and amides useful as high
申请人:The Procter & Gamble Company
公开号:US04692512A1
公开(公告)日:1987-09-08
alpha-L-Aspartyl-D-phenylglycine esters and amides are disclosed to be useful as high intensity sweeteners. These compounds can be used to sweeten a variety of foods, beverages and other oral products.
Boric acid or aluminum salts, especially aluminum chloride, aluminum sulfate and aluminum nitrate and hydrates of said salts, are superior catalysts for preparation of 3-amino-2,2,4,4-tetramethylthietane via the Leuckart reaction.
Branched amides of L-aspartyl-D-amino acid dipeptides and compositions thereof
申请人:PFIZER INC.
公开号:EP0034876A2
公开(公告)日:1981-09-02
Amides of L-aspartyl-D-amino acid dipeptides of the formula
and physiologically acceptable cationic and acid addition salts thereof wherein Ra is methyl, ethyl, n-propyl or isopropyl and R is a branched aliphatic, alicyclic or heterocyclic member which is branched at the alpha carbon atom (the carbon atom bearing the amide nitrogen atom) and also branched again at one or both of the beta carbon atoms, are potent sweeteners which are free from undesirable flavour qualities and of high stability in conventional food processing. Sweetening compositions and sweetened edible compositions of such amides are also claimed
式中 L-天冬氨酰-D-氨基酸二肽的酰胺类
及其生理上可接受的阳离子盐和酸加成盐,其中 Ra 为甲基、乙基、正丙基或异丙基,R 为支链脂环族、脂环族或杂环族成员,该成员在 α 碳原子(含酰胺氮原子的碳原子)上有支链,在一个或两个β碳原子上也有支链。这种酰胺的甜味组合物和甜味可食用组合物也已申请专利。