Construction of functional group reactivity database under various reaction conditions automatically extracted from reaction database in a synthesis design system.

To be able to estimate the reactivity of functional groups under certain reaction conditions, we have stored three types of data: (1) data of change or destruction of the functional groups by the conditions of the reaction conditions; (2) data showing no influence of the reaction conditions on the functional groups; and (3) data showing the relative reactivity of two functional groups in the presence of certain reaction conditions. These three types of data, considered together, form entities that are referenced as "interaction data". These interaction data are used in a synthesis design system called SYNSUP. A new module in our system has been constructed that automatically generates interaction data from the reaction databases. From 15 265 reactions in the database, our program selected 2763 useful reactions with yields of > or =90% and one functional group change. From these useful reactions, data regarding 465 interferences, 815 cases of inert functional groups (under the reaction conditions), and 62 relative rate data could be extracted. In addition, with the use of multiple relative rate datasets, the reactivity of more than two functional groups could be deduced.

Integrated micro flow synthesis based on sequential Br-Li exchange reactions of p-, m-, and o-dibromobenzenes.

A micro flow system consisting of micromixers and microtube reactors provides an effective method for the introduction of two electrophiles onto p-, m-, and o-dibromobenzenes. The Br-Li exchange reaction of p-dibromobenzene with nBuLi can be conducted by using the micro flow system at 20 degrees C, although much lower temperatures (< -48 degrees C) are needed for a batch reaction. The resulting p-bromophenyllithium was allowed to react with an electrophile in the micro flow system at 20 degrees C. The p-substituted bromobenzene thus obtained was subjected to a second Br-Li exchange reaction followed by reaction with a second electrophile at 20 degrees C in one flow. A similar transformation can be carried out with m-dibromobenzene by using the micro flow system. However, the Br-Li exchange reaction of o-dibromobenzene followed by reaction with an electrophile should be conducted at -78 degrees C to avoid benzyne formation. The second Br-Li exchange reaction followed by reaction with an electrophile can be carried out at 0 degrees C. By using the present method, a variety of p-, m-, and o-disubstituted benzenes were synthesized in one flow at much higher temperatures than are required for conventional batch reactions.