A New Improved Procedure for the Synthesis of 4-Formylcarane - Precursor to Sandatrile, a Novel Perfumery Chemical

Stereospecific synthesis of 4-formylcarane (2) has been achieved through hydroboration-carbonylation of DELTA-3-carene. Both the reactions are optimised using sodium borohydride. The method is utilised for the synthesis of sandatrile (3), a novel perfumery chemical.

On The Temperature-Dependence of Regioselectivity in the Amination of Bromobenzotropones

The ipso/cine ratio in the amination of 5-bromo-2,3-benzo- or 2-bromo-4,5-benzotropone shows a dependence upon the temperature at which the reaction is conducted, changing in favour of the ipso-product when the temperature is maintained high, ruling out an aryne-type mechanism. A comparison of independent mechanisms envisaged for the formation of the two isomeric products suggests a two-part reason: (i) at a higher reaction temperature, C-protonation, a step necessary for the formation of the cine-product, could be retarded when a direct internal mode is interfered with by a less efficient external one, and (ii) reketonisation by elimination of bromide, needed to form the ipso-product, is likely to have a high temperature coefficient enabling the rate of its formation to overtake that of the cine-product.

A new quinone from Maesa indica (Roxb)A DC, (Myrsinaceae)

Isolation and structure elucidation of kiritiquinone, a new benzoquinone 2 5 dihydroxy-6-methyl 3 (hemeos 16-enyl)-1 4 benzoquinone from the frutis of Masca indica (Roxb) A DC is described

Enantiospecific approach to AB-ring system of the diterpenes fusicoccanes

Enantiospecific synthesis of the AB ring system of 5-8-5 tricyclic diterpenes fusicoccanes has been accomplished, starting from the readily available monoterpene (R)-limonene employing an reaction as the key step.

Synthesis of Isoquinolines from Indanones-Total Synthesis of Illudinine

Schmidt reaction of 5-methoxy or 7-methoxyindan-1-ones or their derivatives results exclusively in isocarbostyrils which are converted into 6-methoxy or 8-methoxyisoquinolines in good yields. This strategy has been extended to the total synthesis of illudinine methyl ester (1b) starting from methyl 8-methoxy-2,2-dimethyl-7-oxo-1,2,3,5,6,7-hexahydro-s-indacene-4-carboxylate (4).

Chiral Synthons from Carvone. Part 10. Synthesis of (+)-(1S,3S,4S,7S, 8R)-5,7-Dimethyl-10-oxatetracyclo-(5.3.0.03,5,04,8)decan-9-one.

Degradation of the tolyl group in the tricyclic ketone 1b followed by stereospecific reduction of the resultant ketoester (6) furnishes the title compound (4) containing a new tetracyclic framework, establishing the stereochemistry of the aryl group in 1.

Utility of microbes in organic-synthesis - selective transformations of acyclic isoprenoids by aspergillus-niger

Bioconversion of acyclic isoprenoids using a strain of Aspergillus niger results in hydroxylated metabolites with regio- and stereoselectivity. The organism carries out oxidation of the terminal allylic methyl group and the remote double bond in all the compounds tested (I-VII). However, these two activities seem to have preferential structural requirements. When an acyclic isoprenoid with a ketone functionality such as geranylacetone is used as the substrate, the organism also carries out the asymmetric reduction of the keto group. All the metabolites formed have been purified and characterized by conventional spectroscopic methods and quantification has been made by gas chromatographic analyses.

Synthesis, glucose uptake activity and structure-activity relationships of some novel glitazones incorporated with glycine, aromatic and alicyclic amine moieties via two carbon acyl linker

Three series of novel glitazones were designed and prepared by using appropriate synthetic schemes to incorporate glycine, aromatic and alicyclic amines via two carbon linker. Compounds were synthesized both under conventional and microwave methods. Nineteen out of twenty four synthesized compounds were evaluated for their in vitro glucose uptake activity using isolated rat hemi-diaphragm. Compounds, 6, 9a, 13a, 13b, 13c, 13f and 13h exhibited significant glucose uptake activity. Illustration about their synthesis and in vitro glucose uptake activity is described along with the structure activity relationships. (C) 2010 Elsevier Masson SAS. All rights reserved.

Chiral synthons from carvone .20. Stereo- and enantiospecific total synthesis of (-)-valeranone

Stereo- and enantiospecific total synthesis of the irregular sesquiterpene, valeranone, starting from S-6-methylcarvone employing a hydrindanone to decalone ring expansion methodology, is described.

Potassamide induced in situ alkylation of 5,6-dihydroisoquinoline with allyl bromide and Michael acceptors

Potassamide induced in situ alkylation of 4-cyano-3-methoxy-1-methyl-5, 6-dihydroisoquinoline (1a) with allyl bromide gives the 5-allyl- and 5,9-diallyl-5,6-dihydroisoquinolines (1c and 1d), isoquinoline derivative 2 and 4-allyl-1, 2, 3, 4-tetrahydroisoquinolin-3(2H)-one (3a). However, potassamide induced in situ alkylation of In with buten-2-one, mesityl oxide and acrylonitrile results in the formation of only 5-alkylated 5,6-dihydroisoquinoline derivatives 1e-g along with fully aromatised compound 2.

Synthesis of DEF ring skeleton of naulafine alkaloid

6, 8-Dichloro-4, 5-dihydro-2-methyl-[2, 7]acenaphthyridin-1-one (5), obtained from the. reaction of 5-cyano-2, 6-dihydroxy-3, 4-cyclopentenopyridine with Vilsmeier reagent, has been transformed to the key synthon 4a in two steps.

ChemInform Abstract: Enantioselective Formal Total Synthesis of (-)-Homogynolide-A

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Synthetic Studies Towards Prismanes - Rearrangements In Some Pentacyclic Precursors And X-Ray Crystal-Structure Of A Novel Heptacyclic Ether

In order to gain access to the heptacyclic tetraone 3, efforts were directed towards the utilisation of the major 'unwanted' [4 + 2]-adduct 11 of tetrachlorodimethoxycyclopentadiene and norbornenobenzoquinone. Epoxides derived from the diol and dimethoxy derivatives of the adduct 11 undergo facile Wagner-Meerwein rearrangement resulting in the required endo, syn, endo stereochemistry as well as methano-bridge functionalisation to deliver 18 and 24, respectively. However, intramolecular ether formation, occurring via the capture of carbocation intermediate with the transannularly poised oxygen functionality, is a more facile process. Attempts to cleave the ether linkage resulted in the formation of a novel transannularly cyclised twisted bowl shape heptacyclic compound 30 and its structure has been established through X-ray crystallography.