From chemistry-request@server.ccl.net Wed Dec 5 11:17:42 2001 Received: from electra.cc.umanitoba.ca (root@[130.179.16.23]) by server.ccl.net (8.11.6/8.11.0) with ESMTP id fB5GHgi21800 for ; Wed, 5 Dec 2001 11:17:42 -0500 Received: from hultin (hultin.chem.umanitoba.ca [130.179.48.60]) by electra.cc.umanitoba.ca (8.9.0/8.9.0) with SMTP id KAA18304 for ; Wed, 5 Dec 2001 10:17:31 -0600 (CST) From: "Phil Hultin" To: "Computational Chemistry List" Subject: Re: Prediction of Chemical Reactivity Date: Wed, 5 Dec 2001 10:17:31 -0600 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 Whoa! Predicting reactivity is one hell of a problem especially if you want to cover such a wide range of systems. There are many programs that can help you to find reasonable structures for transition states, and more or less plausible activation energies. But to quantitatively predict relative rates simply from the identities of reactant pairs is not trivial! I don't think anyone can do it in a meaningful way. We are working on a "simple" problem related to case 1 below - nucleophilic substitution of primary alkyl chlorides. Believe me, it is consuming large amounts of high powered computer time, and we still haven't convinced referees that we are right in our explanation of the relative reactivities (although I am sure that we are ;-) )! You are not going to find this sort of thing "off the shelf". William Laidig Wrote: >I have a colleague who needs software forpredicting the probability of a aqueous >chemical reaction occurring between a variety of reactive chemicals at around >pH7. Specificly, > 1)nucleophilic substitiution of halogenated compounds > 2) Schiff base formaiton > 3) addition-elimination of acids, esters, amides > 4) nucleophilic adition of aldehydes and ketones > 5) Michael addition of alpha,beta unsaturated compounds > 6) addition by ring cleavage of epoxides > 7) electrophilic substitiution of diazonium salts >I am not up on current synthetic prediction program and would appreciate am >pointers to current software, recommendations, etc. I will summarize responsews >to the list Dr. Philip G. Hultin Associate Department Head and Associate Professor of Chemistry University of Manitoba Winnipeg, MB, Canada R3T 2N2 (vox) 204-474-9814 (fax) 204-474-7608 mailto:hultin@cc.umanitoba.ca http://www.umanitoba.ca/chemistry/