cipitated immediately. But spectroscopic analysis of the product showed that the reaction had taken an unanticipated course. An X-ray crystal structure, ob tained by professor Arnold L. Rheingold and coworkers Louise M. Liable-Sands and Glenn P. A. Yap at the University of Delaware, Newark, showed that the BC12 moiety in the starting compound had in explicably been replaced with AsF4. "We were pretty ecstatic," Manners remarks. He thinks the desired borazine-phosphazene hybrid cation initially forms in the reaction mixture and then reacts with AsF6". That's surprising, he ex plains, because AsF6" is often used as a "noncoordinating" anion to isolate very reactive cations. Indeed, that's why they tried AsF6" for this reaction. But it now seems clear that the thermodynamic driving force for the observed reaction is the cleavage of two As-F bonds to form the more stable B-F bonds in volatile BF2C1, which is eliminated as a gas. Chemistry professor Alan H. Cowley of the University of Texas, Austin, notes that the replacement of boron in the ring with arsenic is "somewhat counterintui tive." The boron is in a borazine-like mol ecule, and "we think of borazine as be ing 'inorganic benzene'—a very stable molecule," he says. "Ergo, boron is not likely to come out of the ring." The dis covery, he adds, "opens up new possibil ities for inorganic ring synthesis." Manners and Gates have found this new synthetic procedure to be a general one. For example, treating the borato phosphazene with Ag[SbF6] leads to two
Unexpected route to inorganic heterocycles "We couldn't believe it when we got it," says chemistry professor Ian Manners of the University of Toronto about his group's discovery of a surprising route to inorganic heterocycles. In the new reaction, the lone boron atom of a boron-phosphorus-nitrogen ring is kicked out and replaced with an other main-group element such as ar senic or antimony. "Skeletal substitution reactions of an atom in an inorganic ring are extremely rare and, to the best of our knowledge, are unprecedented for bo ron-containing rings," the Toronto team states in a paper published last week \J. Am. Chem. Soc, 119, 1125 (1997)]. The starting point for the discovery was a substituted zwitterionic BP2N3 ring called a boratophosphazene, which has been known for many years. The Toron to chemists had previously converted this molecule into an aromatic cationic ring but were looking for a way to do this in the presence of a relatively unreactive counterion, for use in further syn thetic work. They envisioned that a silver salt containing a fluorinated anion might pull a chloride ion off the boron, yielding the desired aromatic BP2N3 cation, a hy brid of a borazine (B3N3) and a phosphazene (P3N3) ring. With this in mind, graduate student Derek P. Gates reacted the boratophos phazene with silver hexafluoroarsenate, Ag[AsF6]. As hoped, silver chloride pre
Reaction replaces ring boron with arsenic, antimony C H3C^
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catalyzed de composition of a diazo ketone to form The Clinton Administration and the na the key carbonyl ylide intermediate. The tion's governors have agreed to a new UCSD synthetic scheme gives an overall federal-state partnership aimed at foster HMAF yield of 15% in 14 steps that in ing economic growth by increasing the clude several novel reactions. contribution of science and technology HMAF has proven effective against to business. breast, lung, and colon tumors in animal Called the U.S. Innovation Partner models [Cancer Res., 57, 279 (1997)] ship, the agreement was announced by and in human cancer cell clones. Toxici Vice President Al Gore at a plenary ses ty studies of the drug in cancer patients sion of the National Governors' Associa are currently under way. The compound tion (NGA) meeting last week in Wash being used in the clinical trials is pre ington, D.C. The partnership will "stimu pared by a semisynthetic process devel late the development and use of new oped by McMorris and scaled up by MGI technologies that can help us meet our Pharma of Minnetonka, Minn. common goals of generating economic A "niche" pharmaceutical company, growth, improving our schools and MGI Pharma licensed the rights to HMAF health care, and better protecting the en and its analogs from the University of vironment at lower cost," Gore told the California in 1993. "We're a 'virtual' governors. company that focuses on clinical devel "This is very important to the gover
White House seals S&T partnership with states
8 FEBRUARY 10, 1997 C&EN
nors now, because there is a [recognition] . . . that the key to long-term economic growth is building new businesses in your state," not just having new businesses re locate to those states, says Joseph A. Kayne, NGA's director of economic devel opment and commerce policy studies. The agreement is the result of months of effort by representatives of 17 states, working through NGA, and a federal in teragency working group consisting of staff from 13 departments and agencies, chaired by Mary L. Good, undersecre tary for technology in the Commerce Department. The partnership will bring representa tives of the states and federal programs together to address major issues and open up the exchange of science and technology information. By "working to gether," Good explains, "we can maxi mize the impact of science and technol ogy on jobs, economic growth, and liv ing standards." Issues already on the table include making federal science and technology resources more available to local govern ments and linking high-tech entrepre neurs and investors via the Internet. According to Gary R. Bachula, deputy undersecretary for technology at Com merce: "This is a recognition that science and technology is the engine for econom ic growth. The partnership is a milestone in the way the federal government and the states do business. We hope that some thing will be accomplished quickly, but re alize it has to be a long-term effort." He says the partnership will utilize existing agency staff and programs and will not need new funding from Congress. David Hanson
Helms moves to block chemical arms pact As he did last year, Senate Foreign Rela tions Committee Chairman Jesse Helms (R-N.C.) is challenging the Clinton Ad ministration on ratification of the Chemi cal Weapons Convention. In a letter to Majority Leader Trent Lott (R-Miss.), Helms says the treaty "is fraught with deficiencies totally inimical to the national security interests of the U.S." He urges Lott to focus the Senate on Republican national security priorities before it takes up the chemical weapons treaty. And when the Senate does consid er the pact, Helms says it must set a num ber of conditions to approval.
