Patents by Inventor Kaoru Maeshima

Kaoru Maeshima has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Process for preparing biotin
    Patent number: 4537973
    Abstract: A process for preparing biotin, characterized in that a compound of the formula: ##STR1## wherein R.sup.1 and R.sup.2 are each hydrogen or benzyl and R.sup.3 is hydrogen or carboxyl, with the proviso that R.sup.1 and R.sup.2 are not simultaneously hydrogen, or a mixture of two or more different compounds of the formula [I] is heated in the presence of an alkanesulfonic acid.
    Type: Grant
    Filed: October 8, 1981
    Date of Patent: August 27, 1985
    Assignee: Sumitomo Chemical Company, Limited
    Inventors: Takeo Takahashi, Kozo Shimago, Kaoru Maeshima
  • Preparation of peptides and cephalosporins
    Patent number: 4043991
    Abstract: An improved process for producing a peptide and a cephalosporin which comprises treating a phosphoramide derivative of the formula: ##STR1## wherein R.sub.1 and R.sub.2 are each an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group, and A.sub.1 is a peptide residue or a cephalosporin residue, with a phosphorus acid to produce a peptide or a cephalosporin of the formula A.sub.1 --NH.sub.2 wherein A.sub.1 is as hereinbefore defined.
    Type: Grant
    Filed: September 22, 1975
    Date of Patent: August 23, 1977
    Assignee: Sumitomo Chemical Company, Limited
    Inventors: Noritaka Hamma, Masataka Fukumura, Kaoru Maeshima, Takenari Nakagome
  • Process for producing cephalosporanic acid derivatives
    Patent number: 3998817
    Abstract: Novel penicillin derivatives of the formula (I) ##STR1## wherein R.sup.1 represents a lower alkyl group and R.sup.2 represents an ester protective group, as hereinafter defined and 7-amino-3-desacetoxycephalosporanic acid derivatives of the formula (II) ##STR2## wherein R.sup.1 represents a lower alkyl group and R.sup.2 represents an ester protective group, which are useful as precursors for the production of cephalosporin derivatives, and an improved process for producing cephalosporin derivatives of the formula (II) above and the formula (III) ##STR3## wherein R.sup.2 is an ester protective group, are disclosed.
    Type: Grant
    Filed: November 14, 1973
    Date of Patent: December 21, 1976
    Assignee: Sumitomo Chemical Company, Limited
    Inventors: Masataka Fukumura, Kaoru Maeshima, Shigeru Okano
  • Process for producing cephalosporins
    Patent number: 3978053
    Abstract: A process for producing a compound of the formula (I) ##SPC1##wherein R.sub.2 is a hydrogen atom or an ester protective group, which is useful as a precursor for the production of cephalosporin derivatives, comprising reacting a phosphoramide derivative of cephalosporin of the formula (II) ##SPC2##wherein R.sub.1 is a lower alkyl group and R.sub.2 is as defined above, with a phosphorus acid. A further embodiment includes preparing the phosphoramide derivative of cephalosporin of the formula (II) by reactng a compound of the formula (III) ##SPC3##wherein R.sub.1 and R.sub.2 are as defined above, with an acid compound.
    Type: Grant
    Filed: November 29, 1974
    Date of Patent: August 31, 1976
    Assignee: Sumitomo Chemical Company, Limited
    Inventors: Noritaka Hanma, Masataka Fukumura, Kaoru Maeshima, Takenari Nakagome