Novel triethylamine mediated thermal reactions of 3-aryl-2-cyanoprop-2-enoic acid derivatives—demethylation, reduction and vinylogation

Harisha, A.; Nayak, Suresh P.; Nagarajan, K.; Row, Tayur N. Guru; Hosamani, Amar A.

doi:10.1016/j.tetlet.2015.01.148

Cited by 5 publications

(10 citation statements)

References 12 publications

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“…A preliminary communication has reported these results. 23 In another experiment acidification was done by aqueous hydroiodic acid and the acidic layer from the experiment was evaporated, washed with diethyl ether to give methyltriethylammonium iodide 7, MR 327-328 • C, which was characterized by 1 stabilized by extensive conjugation with the ortho placed NO 2 group and acrylic derivative at the para position (scheme 3). It is obvious that an analogue of 4 with no methoxyl in the ortho position but only in the meta position which will be also meta located with respect to the acrylic side chain will not undergo demethylation since the methoxyl oxygen atom is not conjugating with the two electron withdrawing groups.…”

Section: Successful Demethylation-synthesis Of Entacaponementioning

confidence: 99%

“…Thus our objective of synthesizing 1 from a Omethylated precursor was realized in moderate yields in un-optimized experiments under mild conditions (scheme 4). 23…”

Section: Successful Demethylation-synthesis Of Entacaponementioning

confidence: 99%

“…The results have been reported in a preliminary communication. 23 We present full experimental details of the demethylation reaction and extension to some similar substrates where demethylation does not occur Amine salts are formed or starting materials are recovered. 23 A few amine salts of water insoluble 1 have been prepared.…”

Section: Introductionmentioning

confidence: 99%

“…23 We present full experimental details of the demethylation reaction and extension to some similar substrates where demethylation does not occur Amine salts are formed or starting materials are recovered. 23 A few amine salts of water insoluble 1 have been prepared. 23 Also recorded are derivation of the single crystal X-ray structure of 2 and extensive application of NMR techniques for deriving the geometry of such molecules.…”

Section: Introductionmentioning

confidence: 99%

“…23 A few amine salts of water insoluble 1 have been prepared. 23 Also recorded are derivation of the single crystal X-ray structure of 2 and extensive application of NMR techniques for deriving the geometry of such molecules.…”

Section: Introductionmentioning

confidence: 99%

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A new synthesis of Entacapone and report on related studies

et al. 2015

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A new synthesis of the catechol-O-methyltransferase (COMT) inhibitor, entacapone (E-isomer) has been achieved under mild conditions by amine-mediated demethylation of the precursor 2-Cyano-3-(3hydroxy-4-methoxy-5-nitrophenyl) prop-2-eneamide, wherein the methoxyl group adjacent to a nitro group gets demethylated under nucleophilic attack. Similar demethylation was achieved on ethyl 2-cyano-3-(3, 4-dimethoxy-5-nitrophenyl) prop-2-enoate, 2-cyano-3-(3,4-dimethoxy-5-nitrophenyl)-N,N-diethylprop-2-enamide, ethyl 2-cyano-3-(3-hydroxy-4-methoxy-5-nitrophenyl) prop-2-enoate and ethyl 2-cyano-3-(4-methoxy-3-nitrophenyl) prop-2-enoate. The scope of demethylation has been studied. Analogues of ethyl 2-cyano-3-(3, 4-dimethoxy-5-nitrophenyl) prop-2-enoate wherein a methoxyl group is not adjacent to a NO 2 group are unaffected and phenolic derivatives yield the amine salts. Entacapone has been converted to salts with organic bases. The crystal structure of the isomer of entacapone (Z-isomer), a significant human metabolite of E-isomer has been established. NMR methods for deriving E and Z geometry and other similar molecules have been successfully established, mainly by studying the proton coupled 13 C spectra. Preliminary studies reveal in vitro activity for some compounds against tuberculosis (TB) and dengue.

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Section: Successful Demethylation-synthesis Of Entacaponementioning

confidence: 99%

“…Thus our objective of synthesizing 1 from a Omethylated precursor was realized in moderate yields in un-optimized experiments under mild conditions (scheme 4). 23…”

Section: Successful Demethylation-synthesis Of Entacaponementioning

confidence: 99%