Cyclobutanones (1) and cyclobutenones (2), R1 and/or R2 = alkyl, aryl, H, often used as synthetic building blocks, could be prepared from N,N‐dialkylamides, trifluorome‐thanesulfonic acid anhydride and alkenes or alkynes in the presence of collidine. N,N‐Dialkyl‐N‐alkylideneammonium(keteniminium) salts occur as intermediates.

Dipeptidyl peptidase IV (DPPIV, EC 3.4.14.5) is a serine type protease with an important modulatory activity on a number of chemokines, neuropeptides and peptide hormones. It is also known as CD26 or adenosine deaminase (ADA; EC 3.5.4.4) binding protein. DPPIV has been demonstrated on the plasmamembranes of T cells and activated natural killer or B cells as well as on a number of endothelial and differentiated epithelial cells. A soluble form of CD26/DPPIV has been described in serum. Over the past few years, several related enzymes with similar dipeptidyl peptidase activity have been discovered, raising questions on the molecular origin(s) of serum dipeptidyl peptidase activity. Among them attractin, the human orthologue of the mouse mahogany protein, was postulated to be responsible for the majority of the DPPIV‐like activity in serum. Using ADA‐affinity chromatography, it is shown here that 95% of the serum dipeptidyl peptidase activity is associated with a protein with ADA‐binding properties. The natural protein was purified in milligram quantities, allowing molecular characterization (N‐terminal sequence, glycosylation type, CD‐spectrum, pH and thermal stability) and comparison with CD26/DPPIV from other sources. The purified serum enzyme was confirmed as CD26.

Background: Congenital disorders of glycosylation (CDG) are usually diagnosed by isoelectric focusing (IEF) of serum transferrin (Tf). The aim of this study was to evaluate capillary zone electrophoresis (CZE) as a diagnostic alternative to IEF. Methods: We performed 792 CZE analyses of Tf, using the CEofix TM -CDT (carbohydrate-deficient transferrin) assay. Peak identification was based on relative migration times (RMTs) to reduce migration variability. Results: Tf profiles comprised three main groups (A-C).Groups A and B were characterized by one or two dominant tetrasialo-Tf peaks, whereas group C showed a widely variable Tf isoform composition. Group A was composed of four subgroups: a major group with a typical Tf profile (considered as reference group), two minor groups with decreased or moderately increased trisialo-Tf isoform, and a group showing the presence of unknown compounds with RMTs similar to mono-and disialo-Tf. However, these compounds were absent on IEF. Group C contained all profiles from patients with confirmed as well as putative CDG. From the reference group, 99% confidence intervals were calculated for the RMTs of the Tf isoforms, and percentiles representing the Tf isoform distributions were defined. Conclusions: All patients with abnormal IEF results and confirmed CDG were identified by CZE; thus, this method can be used as a diagnostic alternative to IEF in a manner suitable for automation. Because whole serum is analyzed, it should be kept in mind that CZE profiles can show substances other than Tf.

Communications to the Editor 4381 4 5(c 1.35, CHC13), IR (CC14) 1749 cm-'. Exclusive endo alkylation of ketone 8 was accomplished, as anticipated, in 90% yield with methyl iodide using lithium diisopropylamide in tetrahydrofuran (0 °C). That the alkylated product 9, [«]25d -414°( c 1.40, CHCI3), was indeed the product of exclusive endo alkylation was evident from examination of its NMR spectrum at 250 MHz which revealed the C(3) exo proton as a quartet of doublets located at 2.46 (J3 4 = 3.3, Jh ch3 = 7.0 Hz). Baeyer-Villiger oxidation of 9 using basic hydrogen peroxide in aqueous methanol-tetrahydrofuran gave rise to the sensitive hydroxy acid 10 which upon treatment with boron 9 10 trifluoride etherate in methylene chloride at 0 °C rearranged (85% overall) solely to intermediate 4, [a]25p +153°( c 1.50, CHCI3), with the expected transfer of chirality from C(14) -C(16) (steroid numbering). Reduction (¡'-BU2AIH, toluene, -78 °C) of lactone 4, followed by condensation with isopentylidenetriphenylphosphorane (generated with sodium íe/7-amylate in benzene), provided in 50% overall yield dienol 5 as a mixture of double-bond isomers about the C(22)-C(23) olefinic linkage. The required transfer of chirality from C( 16) -* C( 14) was achieved classically by a two-step process. Allylic alcohol 5 was converted (ethyl vinyl ether, Hg(OAc)2, reflux) into its corresponding vinyl ether (82% yield) which upon heating in decalin at 200 °C (5 h) under nitrogen generated aldehyde 6 in 90% yield.7 (6) Our [a]25o for optically pure i in methanol (c 1.00) was +75.2°; however, this value rapidly drops to +60°. Use of dioxane(c 1.00) gave [a]25D +81.8°consistently.

Cyclobutanone (1) und Cyclobutenone (2), R1 und/oder R2 = Alkyl, Aryl, H, häufig verwendete Synthesebausteine, konnten aus N,N‐Dialkylamiden, Trifluormethansulfon‐säureanhydrid und Alkenen bzw. Alkinen in Gegenwart von Collidin hergestellt werden. Als zentrale Zwischenstufe treten N,N‐Dialkyl‐N‐alkylidenammonium(Keteniminium)‐Salze auf.