THE CHEMICAL WORLD THIS WEEK
of a completely synthetic route for commercial penicillin. As one company puts it, "A total synthesis probably isn't practical unless it yields entirely new types of penicillin." New entities are exactly what Dr. Bose and his associates have made in their syntheses at Stevens. In the product from isobutyraldehyde (see diagram for synthetic route), the substituent group, C 0 2 C H 3 , has been moved from the usual C-3 to the C-5 position. The key discovery in this synthesis is the action of azidoacetyl chloride to convert the thiazoline intermediate to a bicyclic /^-lactam. This compound is then changed to penicillin by reduction, hydrolysis, acylation, and esterification. In synthesis of the stereoisomer, the penicillamine goes through formylation and ring-closure steps to form an intermediate thiazoline. Thereafter, reaction with azidoacetyl chloride and triethylamine and subsequent reduction and acylation give the product penicillin.
ACCELERATORS:
Full-Time LINAC The University of Illinois is building at its Urbana campus a superconducting linear accelerator (LINAC) capable of high-energy physics research with a continuous electron beam. Preliminary operation of the 30-m.e.v. LINAC is expected within a year. Full operation is scheduled for 1970. The Illinois project parallels work at Stanford University where physicists are building a similar, but larger, machine (C&EN, May 6, page 18). As a second step by 1972 Illinois plans to incorporate LINAC into a microtron. The microtron will accelerate the electron beam to 600 m.e.v. by passing the beam through LINAC 20 times. Recirculation of the beam will be accomplished by the microtron's "racetrack" design wherein two magnets, one at each end of the accelerator, turn the beam and send it back down the "stretch/' The microtron will replace the university's 340-m.e.v. betatron. The National Science Foundation will supply a $500,000 grant for part of the more than $2 million cost of Illinois3' LINAC. Funds for the microtron have not yet been procured. Dr. Peter Axel and Dr. Alfred O. Hanson of the university's department of physics are in charge of the project. By using superconductivity, LINAC will produce electrons in a continuous beam instead of in bursts as other accelerators do. The continuous beam capability gives LINAC a duty 16 C&EN JULY 15, 1968
RESEARCH SUBMERSIBLE. North American Rockwell's Beaver 4, to be launched in September, will be the first vessel of its kind available to industry
factor of 100%, Prof. Axel says. This compares with a 0.1 to 0.2% duty factor for present LINACS and a 1 to 7% factor for most others being designed, he says. The 100% capability allows an experiment which might take a month on present equipment to be performed in a day. "A high duty factor is needed in many important experiments," Dr. Axel says. "Often the duty factor, rather than beam intensity, limits what can be done. The superconducting LINAC will open entirely new opportunities in nuclear research." For example, deep structure nucleus studies will be possible, Dr. Hanson says, and the energy, momentum, and the time of recoiling protons and neutrons can be more accurately determined. From this data the energy levels within a nucleus are determined. The Illinois LINAC accelerates electrons in a series of cylindrical microwave accelerator cavities. These will form a tube 15 feet long and 1 foot in diameter. Liquid helium will maintain the temperature at 1.8° K.
OCEANOGRAPHY:
Sleeping Giant Stirs The industrial potential of oceanography can be compared to a sleeping giant, Frederick J. Close, chairman, told the 4th Annual Conference and Exposition of the Marine Technology Society last week in Washington, D.C. The giant—in the form of exploitation of chemical and mineral resources of the oceans—is stirring. However, more money, brains, and de-
vices are needed to support a national effort for this exploitation, Mr. Close added. Examples of some results that money and brains are already providing were shown in several submersible systems at the MTS exposition. One of those exhibited—Beaver Mark IV, developed by North American Rockwell's Ocean Systems Operations—will be the first manned research submersible available to industry. However, it must first go through a one-year testing period after its official launching in mid-September. This highly maneuverable workboat will be equipped with two manipulator arms, a tool exchange system, and other equipment for research, recovery, construction, survey, and experimentation. North American Rockwell says that while Beaver is designed primarily for research, the vehicle will be able to perform jobs in underwater construction and in petroleum-related projects. Important features of the 25-footlong vessel include capability for diver lockout to depths of 1000 feet and dry transfer of personnel to undersea stations at depths to 2000 feet. The submarine will be available for lease from $6000 to $10,000 per day, a company spokesman tells C&EN. He adds that many petroleum companies, including Mobil Oil, have shown interest in the vehicle. Also unveiled at the MTS exposition was another manned submersible called the Guppy. Built by Sun Shipbuilding & Dry Dock Co., Chester, Pa., the vessel will carry a pilot and an observer for offshore oil exploration and
