75400-57-6Relevant academic research and scientific papers
METHODS FOR FORMING SATURATED (HETERO)CYCLIC BORYLATED HYDROCARBONS AND RELATED COMPOUNDS
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Paragraph 0058, (2018/03/25)
The disclosure relates to methods for forming at least partially saturated cyclic and heterocyclic borylated hydrocarbons, as well as related compounds, which can be precursor compounds in the synthesis of any of a variety of pharmaceutical or medicinal compounds with a desired structure and/or stereochemistry for drug synthesis or drug candidate evaluation. The methods generally include reduction of an unsaturated cyclic or heterocyclic borylated hydrocarbon having a boron-containing substituent at an sp2-carbon, where such reduction converts the sp2-carbon to an sp3-carbon at the point of attachment of the boron-containing substituent. The methods can exhibit a selectivity for syn-addition during reduction, which can provide stereospecific products, such as when the unsaturated cyclic or heterocyclic reactant is multiply substituted with boron groups and/or other functional groups.
Synthetic endeavors toward 2-nitro-4-alkylpyrroles in the context of the total synthesis of heronapyrrole C and preparation of a carboxylate natural product analogue
Schmidt, Jens,Stark, Christian B. W.
, p. 1920 - 1928 (2014/04/03)
The synthesis of 2-nitro-4-oligoprenyl-substituted pyrrole derivatives relevant to the heronapyrroles and related natural products was investigated. Among numerous approaches, nitration of a 3-farnesyl-substituted unprotected pyrrole using AcONO2 gave the best results, albeit still with unsatisfactory yield and regioselectivity. Therefore, the synthesis of (-)-heronapyrrole C acid, an analogue of the naturally occurring antibiotic heronapyrrole C carrying a bioisosteric carboxylate in place of the nitro group, was examined. In lieu of the unsatisfactory nitration, a regioselective acylation with Cl3CCOCl was carried out (>8:1 regioselectivity, in contrast to the 1:1.3 ratio for the nitration). The trichloromethyl ketone was converted to the desired acid in a haloform reaction at the final stage of the synthesis. Further key steps of the analogue synthesis involved a position- and stereoselective Corey-Noe-Lin dihydroxylation and an organocatalytic double Shi epoxidation. A biomimetic polyepoxide cyclization cascade established the bis-THF backbone. Thus, (-)-heronapyrrole C acid was synthesized in eight steps (14.5% overall yield) from commercially available starting materials.
Rearrangement of 2,5-bis(silylated)-N-boc pyrroles into the corresponding 2,4-species
Mirebeau, Jean-Hugues,Haddad, Mansour,Henry-Ellinger, Martin,Jaouen, Gerard,Louvel, Julien,Le Bideau, Franck
supporting information; experimental part, p. 8890 - 8892 (2010/03/01)
(Chemical Equation Presented) The rearrangement of 2,5-bis(silylated)-N-Boc pyrroles in their 2,4-isomers is shown to proceed under mild acidic conditions. A reasonable mechanism, based on literature as well as experiments, is proposed to rationalize this
Synthesis of rhazinicine by a metal-catalyzed C-H bond functionalization strategy
Beck, Elizabeth M.,Hatley, Richard,Gaunt, Matthew J.
, p. 3004 - 3007 (2008/12/23)
(Chemical Equation Presented) Iterative and regioselective metal-catalyzed C-H bondfunctionalization has been utilizedto develop a strategy for the first total synthesis of the pyrrole alkaloid rhazinicine (see scheme).
CONVENIENT SYNTHETIC EQUIVALENTS OF 2-LITHIOPYRROLE AND 2,5-DILITHIOPYRROLE.
Chen, Wha,Cava, Michael P.
, p. 6025 - 6026 (2007/10/02)
Bromination of pyrrole by 1,3-dibromo-5,5-dimethylhydantoin, followed by direct reaction with BOC anhydride and DMAP, affords the stable N-BOC derivatives of 2-bromopyrrole and 2,5-dibromopyrrole.Lithium-halogen exchange of the latter with n-butyllithium generates the N-BOC derivatives of 2-lithiopyrrole, 2,5-dilithiopyrrole or 5-bromo-2-lithiopyrrole,which react with various electrophiles to give substituted N-BOC pyrroles in excellent yield.
Synthesis and Reactions of N-Protected 2-Lithiated Pyrroles and Indoles. The tert-Butoxycarbonyl Substituent as a Protecting Group
Hasan, Iltifat,Marinelli, Edmund R.,Lin, Li-Ching Chang,Fowler, Frank W.,Levy, Alan B.
, p. 157 - 164 (2007/10/02)
N-(tert-Butoxycarbonyl)pyrrole and N-(tert-butoxycarbonyl)indole have been prepared and lithiated at the 2-position with lithium 2,2,6,6-tetramethylpiperidide and tert-butyllithium, respectively.These lithium reagents react with a variety of electrophiles to give the 2-substituted N-(tert-butoxycarbonyl)pyrroles and N-(tert-butoxycarbonyl)indoles.The N-(tert-butoxycarbonyl) substituent may be removed rapidly and in high yield from the pyrrole derivatives under basic conditions.For the indole derivatives, the protecting group may be removed with either acidic or basic conditions.
