—C–H And C–C Bond Activations Join Hands “Separate activation reactions and electrophilic addition are combined in a single process” C –H bonds can be activated selectively to convert them to C–C and C-heteroatom bonds, and C–C bonds can be activated selectively to convert them to C–H, C–Si, and other bonds, but these techniques have been carried out separately.
by Stu Borman | December 16, 2013
—Double C-F/C-H bond activation “” Superstrong C-F bonds don't readily lend themselves to activation and subsequent reaction, but that hasn't stopped chemists from edging closer to a general method for C-F activation. In one of the latest efforts, Kohei Fuchibe and Takahiko Akiyama of Gakushuin University, in Tokyo, report a "double activation" reaction in which a C-F bond and a C-H bond in close proximity in the same molecule are jointly activated, leading to ring-closing and formation of a new molecule (J.
January 30, 2006
He would not be surprised, however, to find that C-peptide doesn't have a receptor. No receptor for C-peptide has yet been found. Previous work suggested that any effects of C-peptide require the presence of insulin as well, but Spence and his colleagues see the increased ATP release even in the absence of insulin. The catch is that C-peptide must first be activated by a transition-metal ion. Spence and coworkers stumbled upon the metal connection. When they reconstituted commercial C-peptide, its activity would disappear after a day. Spence took a vial of fresh C-peptide to his colleague Gavin E. Reid, a mass spectrometrist at Michigan State, who told him that the C-peptide had Fe2+ in it.
by Celia Henry Arnaud | January 14, 2008
The C&EN Archives—the digital collection of all issues of C&EN from its introduction in 1923 through 2009—for example, debuted in November 2010; all 2010 issues were added to the C&EN Archives in the first quarter of 2011. We introduced C&EN Mobile, another CPAP project, in August of this year. All issues of C&EN are now available for free to ACS members on their smartphones and tablets, an important new member benefit. The most visible manifestation of the completion of CPAP 1.0 is the redesign of C&EN Online. Regular users of C&EN Online will notice the changes immediately. If you aren’t a regular user of C&EN’s online edition, please check it out at cen-online.org. The C&EN Online home page has been overhauled in response to numerous user comments to make it less dense and more user-friendly.
by Rudy M. Baum | October 31, 2011
—Extreme C–C Bonds “Highly strained cyclopropane-based molecules help chemists refine ideas about chemical bonding” THE CARBON-CARBON BOND is arguably the most fundamental connection in all of chemistry. Yet a century after chemists began in earnest to unravel the mysteries of chemical bonding, the intricate details of C–C bonds are still unfolding.
by Stephen K. Ritter | May 11, 2009
—Catalyst activates tertiary C–H bonds “Dirhodium agent functionalizes specific bonds without need for nearby directing groups” In recent years, chemists have devised powerful synthetic tools that activate C–H bonds to allow them to install new substituents. But many C–H bonds still cannot be functionalized selectively. Researchers have now expanded the C–H activation toolkit by developing a way to add groups to specific tertiary C–H bonds, carbon atoms bonded to three other carbons, without the usual need for directing groups to control selectivity. Alkyl compounds often contain many fairly unreactive C–H bonds that are difficult to distinguish.
by Stu Borman | November 21, 2017
—Chemists break C–C bond record “New hydrocarbon compound contains a 1.806-Å-long bond that stretches beyond theoretical limit, researchers claim” The single carbon-carbon bond is among the most familiar covalent connections in organic compounds. But a new study suggests that chemists have yet to fully explore the limits of this basic bond.
by Tien Nguyen | March 08, 2018
—Extreme C–c Bonds “Highly strained cyclopropane-based molecules help chemists refine ideas about chemical bonding” /articles/87/i19/Extreme-Cc-Bonds.html 20091105 Highly strained cyclopropane-based molecules help chemists refine ideas about chemical bonding 87 19 /magazine/87/8719.html Extreme C–c Bonds xxtagxx, xxtagxx, xxtagxx scitech Stephen K. Ritter, C&EN Washington synthesis Image Description. Image Title Credit Extreme C–c Bonds Chemical & Engineering News Extreme C–c Bonds Extreme C–c Bonds
by Stephen K. Ritter, C&EN Washington | November 05, 2009
—C. C. Cheng “” Chia Chung (C. C.) Cheng, 91, died on Dec. 2, 2016, in Sugar Land, Texas. “C. C. Cheng was a most gracious and humble man. Among his many accomplishments, one compound he synthesized, mitoxantrone, is still used today for the treatment of breast cancer and nonlymphoid leukemia. He published over 300 scientific research papers and was highly regarded and sought after for his insight and technical prowess as a medicinal chemist.
by Linda Wang | May 15, 2017