Project TE103, existing example No. A7
Level / Category (ies)
CL 1b, 2b3, 3b
AL 1b, 2b3, 3b
Documents (Classification is based on US3644377)
US 3644377
FR 2089348
DE 2116159
Short Version of the Disclosure
The document discloses the process of the preparation of a compound of formula I, i.e. 4pyridylthio acetic acid (see column 2 line 15).
The process comprises reacting a compound of formula II, i.e. 4-(pyridyl) pyridinium (see
column 2 line 25), with 2-mercaptoacetic acid in water.
Representative Prior Art
(4-pyridylthio) acetic acid is an old compound known in the art.
One article teaches the preparation of ethyl (4-pyridylthio) acetate by the reaction of 4-(lpyridyl)pyridinium chloride hydrochloride with ethyl 2-chloroacetate in the presence of
hydrogen sulfide. The hydrolysis of the ethyl (4-pyridylthio)acetate to (4- pyridylthio) acetic
acid was then accomplished in a two step reaction (see column 1 lines 36-46).
Another article teaches the preparation of (4-pyridylthio) acetic acid by the mixture of 4thiopyridone with 2-chloroacetic acid. The disadvantage of the process is the necessity of
using 4-thiopyridone, an expensive starting material (see column 1 lines 47-52).
Invention Information
I1. The present invention relates to a process for the preparation of 4(pyridylthio)acetic acid
which is a valuable intermediate in the preparation of biologically active cephalosporins.
4-(pyridylthio)acetic acid is claimed to be prepared in high yield (about 70 % to 95 %)
without the use of 4-thiopyridone by reacting a compound of the formula II (column 2 line
25) with 2-mercaptoacetic acid in water.
Additional Information (only for Category 3)
A1. Example 4 discloses the preparation of 7-[alpha(4-pyridylthio)acetamido]cephalosporanic
acid (see formula in Example 4) when prepared from 7-aminocephalosporanic acid by
acylation of the 7-amino group thereof using compound of formula I .
Identification of Potential Subclasses
A chemist would recognise that the claimed compounds are heterocyclic compounds, and that
such compounds should be classified in subclass C07D.
Subject Matter
Tool
Query
IPC Places
I1
Catchword index
HETEROCYCLIC compounds
C07D
A1
Catchword index
HETEROCYCLIC compounds
C07D
Analysis and Selection of Classification Symbols
Core Level
Inventions dealing with the preparation of chemical compounds are classified in the groups
for the compound prepared (see Note (3) of C 07 class notes). Classification is made in the
last appropriate subclass of subclasses C07C to C07K (see Note (2) of the C07 class notes).
C07D is a last place priority area and has special notes to follow which affects classification
(Notes 5a and 5c).
I1. A (process of preparation of a) heterocyclic compound containing six-membered rings, not
condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or
more double bonds between ring members is classified in C07D213/00.
A1. A (process of preparation of a) heterocyclic compound containing 5-thia-1-azabicyclo
[4.2.0]octane, e.g. cephalosporins is classified in C07D501/00.
Invention information is always listed first ahead of additional information, therefore
C07D213/00 is the symbol that appears first here.
Advanced Level
Inventions dealing with the preparation of chemical compounds are classified in the groups
for the compound prepared (see Note (3) of C 07 class notes). Classification is made in the
last appropriate subclass of subclasses C07C to C07K (see Note (2) of the C07 class notes).
C07D is a last place priority area and has special notes to follow which affects classification
(Notes 5a and 5c).
I1. A (process of preparation of a) heterocyclic compound containing six-membered rings, not
condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or
more double bonds between ring members is classified in C07D213/00.
C07D213/70 applies there, as there is a sulfur atom directly attached to the heterocyclic ring.
A1. A (process of preparation of a) heterocyclic compound containing 5-thia-1-azabicyclo
[4.2.0]octane, e.g. cephalosporins is classified in C07D501/00.
The compound containing 5-thia-1-azabicyclo [4.2.0]octane has a nitrogen atom directly
attached in position 7, with a double bond between positions 2 and 3, and with the 7-amino
radical acylated by carboxylic acids containing a hetero ring. It should be classified in
C07D501/34.
Invention information is always listed first ahead of additional information, therefore
C07D213/70 is the symbol that appears first here.
Analysis of Group
Selection
IPC CL
Subject
Matter
Analysis of Subclass
Selection
Subclass
I1
Rule 5(a) under
subclass title
C07D
Last place rule
C07D213/00
C07D213/7
0
A1
Rule 5(c) under
subclass title
C07D
Last place rule
C07D501/00
C07D501/3
4
IPC AL
IPC(2006)
Complete Classification
The complete core and advanced level classification for this document based on the above
analysis is as follows:
Core level
Int. Cl. (2006)
C07D213/00
C07D501/00
Advanced level
Int. Cl.
C07D213/70 (2006.01)
C07D501/34 (2006.01)