摘要:
Disclosed is a process for selectively producing (D+1)-member heterocyclic compounds from corresponding unactivated dienes or derivatives thereof in the presence of a transition metal or lanthanide catalyst or a precursor thereof, relative to D-member heterocyclic rings.
摘要:
The invention relates to a method for the 1,3 dipolar cycloaddition of organic compounds, characterized in that the reaction is carried out in a microreactor.
摘要:
The present invention relates to novel stabilized phosphorous ylides and processes for their preparation. More particularly, the present invention relates to a process for substituting the carbonyl oxygen of 2-formyl- or 2-oxoalkylidenetriphenyl-phosphoranes (OATP) by other stabilizing groups to form novel compounds having an increased tendency to form complexes or compounds which absorb in the visible region of the spectrum.The compounds according to the present invention areCompounds of the formula (1)Ph.sub.3 .dbd.CH--C(R).dbd.Nu (1)wherein R is hydrogen, a C.sub.1 -C.sub.5 -alkyl, C.sub.1 -C.sub.3 -fluoroalkyl or perfluoroalkyl radical, an unfluorinated or fluorinated C.sub.6 -C.sub.14 -aryl radical or a group OCH.sub.3 ; andNu is S, Se, C(CN).sub.2, NH, PhN, PhNHN, ##STR1## or a radical of the formulae (a), (b), (c), (d) or (e) ##STR2## wherein Z is C(CH.sub.3).sub.2, S or N(CH.sub.3) and n=1 or 2 (provided that the combinations R.dbd.Ar, SAlk or OAlk and Nu.dbd.NPh, and the combinations R.dbd.H, Alk or aryl and Nu.dbd.S are excluded) are disclosed, as well as methods for making them.
摘要:
7.beta.-Amino-3-hydroxy-1-carba(1-dethia)-3-cephem-4-carboxylic acid esters are provided via cyclization of cis-3-(substituted amino)-1-(2-substituted 2-oxoethyl)-4-substituted azetidinones. The 7.beta.-amino-3-hydroxy-1-carba (1-dethia)-3-cephem-4-carboxylic acid esters are useful chiral intermediates to .beta.-lactam antibiotics.
摘要:
The magnesium complexes of cyclic hydrocarbons and conjugated dienes, such as 1,2-dimethylenecycloalkanes and 1,3-butadienes, are readily prepared in high yields using highly reactive magnesium. Reactions of these (2-butene-1,4-diyl)magnesium reagents with electrophiles such as dibromoalkanes, alkylditosylates, alkylditriflates, bromoalkylnitriles, esters, or amides serve as a convenient method for synthesizing carbocyclic systems. Significantly, carbocycles prepared by this method contain functional groups such as the exocyclic double bond or a keto group in one of the rings which could be used for further elaboration of these molecules. Furthermore, fused bicyclic systems containing a substituted five-membered ring can be conveniently prepared at high temperatures by the reactions of (2-butene-1,4-diyl)magnesium complexes with carboxylic esters or acid halides whereas low temperatures lead to regioselective synthesis of .beta.,.gamma.-unsaturated ketones. Additionally, .gamma.-lactones, including spiro .gamma.-lactones, can be easily prepared in a one pot synthesis from the reaction of (2-butene-1,4-diyl)magnesium complexes with a ketone or aldehyde and carbon dioxide.
摘要:
The invention relates to a process for the preparation of pilocarpine derivatives from a 5-formyl-imidazole derivative of the formula II ##STR1## in which R.sup.1 is hydrogen, a low molecular weight straight-chain or branched alkyl chain having 1-8 C atoms, or a substituted or unsubstituted carbocyclic radical.
摘要:
The magnesium complexes of cyclic hydrocarbons containing conjugated dienes, such as 1,2-dimethylenecycloalkanes, and 1,3-butadienes, are readily prepared in high yields using highly reactive magnesium. Reactions of these (2-butene-1,4 diyl)magnesium reagents with electrophiles such as dibromoalkanes, alkylditosylates, alkylditriflates, bromoalkylnitriles, esters, or amides serve as a convenient method for synthesizing carbocyclic systems. Significantly, carbocycles prepared by this method contain functional groups such as the exocyclic double bond or a keto group in one of the rings which could be used for further elaboration of these molecules. Furthermore, fused bicyclic systems containing a substituted five-membered ring can be conveniently prepared at high temperatures by the reactions of (2-butene-1,4-diyl)magnesium complexes with carboxylic esters or acid halides whereas low temperatures lead to regioselective synthesis of .beta.,.gamma.-unsaturated ketones. Additionally, .gamma.-lactones, including spiro .gamma.-lactones, can be easily prepared in a one pot synthesis from the reaction of (2-butene-1,4-diyl)magnesium complexes with a ketone or aldehyde and carbon dioxide. Also, .delta.-lactones can be easily prepared in a one pot synthesis from the reaction of (2-butene-1,4-diyl)magnesium complexes with epoxides followed by reaction with CO.sub.2. Use of .alpha.-hydroxy epoxides without the addition of CO.sub.2 leads to the synthesis of vicinal diols. Chiral epoxides lead to chiral alcohols.
摘要:
An alkylative cycloaddition method is provided that is particularly useful for the synthesis of many of the Vitamin D analogues with differing side chains. Thus, a preferred synthesis is of Vitamin D analogues having a side chain R.sub.1 where a substantially geometrically pure first precursor having the structure ##STR1## and a second precursor are provided, the second precursor being a 1,7 enyne. These precursors are reacted in the presence of a palladium catalyst to form compounds having the structure ##STR2## where R.sub.2 hydrogen, hydroxyl, lower alkoxy, fluorine, or a protecting group, and R.sub.3 is hydrogen, hydroxyl, lower alkoxy, fluorine, or a protecting group.
摘要:
The invention is a process for the preparation of an aromatic hydrocarbon with a cyclobutene ring fused to the aromatic hydrocarbon which comprises, dissolving an ortho alkyl halomethyl aromatic hydrocarbon in an inert solvent and pyrolyzing the solution of ortho alkyl halomethyl aromatic hydrocarbon in the inert solvent under conditions such that the ortho alkyl and halomethyl substituents form a cyclobutene ring thereby forming an aromatic hydrocarbon having a fused cyclobutene ring.
摘要:
This invention provides a convenient and commercially adaptable process for the preparation of vinylcyclopropane derivatives in high yields. The process involves reacting an alkylating agent and an activated methylene compound in the presence of an onium compound, an alkali metal compound and water, which while only necessary in trace amounts can be present in substantial quantities.