Novel Cephalosporins Having a Benzothiopyran Group. 2. Synthesis and Biological Activity of Catecholic Benzothiopyran Group at the C-3 Side Chain.

Obi, Kinichi; Saito, Tatsuhiro; Kojima, Akihiko; Fukuda, Hideyuki; Hirai, Keiji; Suzue, Seigo

doi:10.7164/antibiotics.48.278

Cited by 4 publications

(1 citation statement)

References 9 publications

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“…2,4 The benzothiopyrans show also pharmacological properties as antibacterials, antiallergics, antitumoral, sedatives, hypoglycemic and hypocholesterolemic; other interests lie in the treatment of AIDS. 2,[5][6][7][8][9] The methods of preparation of benzothiopyrans reported in the literature consist in the cyclocondensation of arylthiopropenes, arylthiopropanoic or arylthioacrylic acids and esters, the cyanoethylation of mercaptocarboxylic acids and the polar cationic [4 + +2] between chloromethylphenylsulfide and styrene or trans -stilbene or phenylacetylene. [10][11][12][13][14][15][16][17] In this work we describe a new one-step synthesis of benzothiopyranic derivatives.It was previously found that the thiomethyl and the sulfonylalkyl groups are able to promote the metallation of the ortho -and α -positions.…”

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confidence: 99%

A New One-Step Synthesis of Benzothiopyran Derivatives

Cabiddu¹,

Cabiddu²,

Cadoni³

et al. 1998

Synthesis

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Methylthio)-and (isopropylthio)benzene are useful synthetic intermediates to prepare bimetallated intermediates which, after reaction with α -diketones, lead to benzothiopyranic derivatives in one-step and with good yields.A few benzothiopyranic compounds have been detected in crude oil 2 and in several sulfur rich sediments: 3 the lack of natural availability of this heterocyclic ring makes its de novo synthesis necessary. The importance of these compounds lies in their use in the dye industry and as photoactive agents. 2,4 The benzothiopyrans show also pharmacological properties as antibacterials, antiallergics, antitumoral, sedatives, hypoglycemic and hypocholesterolemic; other interests lie in the treatment of AIDS. 2,5-9The methods of preparation of benzothiopyrans reported in the literature consist in the cyclocondensation of arylthiopropenes, arylthiopropanoic or arylthioacrylic acids and esters, the cyanoethylation of mercaptocarboxylic acids and the polar cationic [4 + +2] between chloromethylphenylsulfide and styrene or trans -stilbene or phenylacetylene. [10][11][12][13][14][15][16][17] In this work we describe a new one-step synthesis of benzothiopyranic derivatives.It was previously found that the thiomethyl and the sulfonylalkyl groups are able to promote the metallation of the ortho -and α -positions. [18][19][20][21] This method allows to prepare sulfur compounds orthoand α -dilithiated by direct bimetallation of alkylaromatic thioethers and sulfones using two molar equivalents of butyllithium. The lithiated intermediates can react with bifunctionalized compounds as esters and acyl halides to give benzo[ b ]thiophenes.Attempts to prepare benzothiopyrans by reaction of diethyloxalate with these dilithiated species were unsuccessful. In fact this compound reacts with only one ester group because the carbonyl carbon of the intermediate ketone is more electrophilic than the ester. 19Now we have successfully performed the synthesis using α -diketones. The bimetallated species obtained from (methylthio)-( 1a ) and (isopropylsulfonyl)arenes ( 1b,c ) were reacted with equimolar amounts of α -diketones in tetrahydrofuran at -80°C. The reaction mixture was allowed to warm up to room temperature with stirring. The benzothiopyran derivatives 3a-f were obtained in good yields (55-65%) (Scheme, Tables 1 and 2), thus showing that both lithiated centres attack the two carbonyl carbons. The reaction was diastereoselective giving only the isomer with the two hydroxy groups in the trans diaxial configuration. The stereochemistry of compounds 3a-f was determined by NOE difference and NOESY experiments.Solutions of butyllithium in hexane were purchased from Aldrich and were analyzed by the Gilman double titration method. 22 Analytical TLC plates and silica gel (230-400 mesh) were purchased from Merck. IR spectra were recorded on a Perkin-Elmer 1310 grating spectrophotometer using NaCl plates. 1 H and 13 C NMR spectra were recorded on a Varian VXR-300 spectrometer. Mass spectra were obtained at 70 eV with a Hewlett-Pac...

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confidence: 99%

A New One-Step Synthesis of Benzothiopyran Derivatives

Cabiddu¹,

Cabiddu²,

Cadoni³

et al. 1998

Synthesis

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ChemInform Abstract: Novel Cephalosporins Having a Benzothiopyran Group. Part 2. Synthesis and Biological Activity of Catecholic Benzothiopyran Group at the C‐3 Side Chain.

et al. 1995

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Novel Cephalosporins Having a Benzothiopyran Group. Part 2. Synthesis and Biological Activity of Catecholic Benzothiopyran Group at the C-3 Side Chain.-A number of title compounds of type (III) and (IV) are prepared. Most of them show excellent activity against Gram-negative bacteria including P. aeruginosa. (IVb) and (IVc) are highly potent against Gram-negative and Gram-positive bacteria.-(OBI, K.; SAITO, T.; KOJIMA, A.; FUKUDA, H.; HIRAI, K.; SUZUE, S.; J. Antibiot.

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