The Mechanism of Addition of Diazo-alkanes to Cyclopropanones

The addition of diazo-alkanes to cyclopropanones yields cyclobutanones whose structures may be predicted on the basis of conformational regulation of the migrating carbon-carbon bond

Methodology for sampling and analysis of lipids in aerosols from the remote marine atmosphere

A procedure is described for the collection of remote marine aerosol samples by high-volume filtration, cascade impaction, dry fallout collection and rain. Samples were analyzed quantitatively for five classes of naturally occurring lipids (n-alkanes, wax esters, fatty alcohols, sterols, and fatty acids) and polycyclic aromatic hydrocarbons (PAHs). Air samples (4,000-10,000 m3) were collected on glass fiber filters under automatic control. Rain samples of 1-5 L were collected on an event basis. Filters and rain samples were extracted with methylene chloride. The extracts were fractionated into discrete chemical classes by silca-gel absorption chromatography. The fractions were derivatized if necessary and analyzed by HRGC and HRGC/MS. A second fiter extraction was required for fatty acid salt analysis. Internal standards were used to quantify recoveries and concentrations. Mean recoveries relative to the internal standards were 96.5% for C12-C36 n-alkanes, 96.4% for C12-C30 n-fatty acids, 92.5% for C12-C30 n-fatty alcohols and 93.3% for cholesterol. Typical blanks and concentrations for remote marine aerosol and rain samples are described and compared with other methods used in coastal marine, rural and suburban sampling locations.Prepared for the National Science Foundation under Grants OCE 77-12914 and OCE 81-11947 as part of the Sea-Air Exchange (SEAREX) Program

Favorskii rearrangement of some α-Bromo-ketones

The base-induced rearrangement of α-halogenoketones to give carboxylic acid derivatives (Favorskii rearrangements) occurs by at least two mechanisms. The stereochemistry, and structure of many Favorskii products can be explained in terms of a cyclopropanone intermediate. However, a "benzylic-like" rearrangement appears to operate when the substrate ketone bears no α'-hydrogen, when the α'-hydrogen is relatively non-acidic, or when steric or strain factors inhibit cyclopropanone formation. In addition, the formation of a dipolar intermediate which may precede (or follow) cyclopropanone formation is supported by theoretical considerations, loss of stereospecificity upon rearrangement in polar solvents, the formation of α-substitution products as a side reaction, and the trapping of a possible Favorskii intermediate "dehydrohalogenate" to form a common intermediate leading to the same product

Hydrographic and nutrient data from R/V Knorr cruise 73, leg 2 : February to March, 1978 : off the coast of Peru

In February and March of 1978 a major cruise was undertaken on the R/V KNORR off the Peruvian coast near 15°S in order to investigate the organic biogeochemical processes associated with upwelling areas. The purpose of this report is to collate the large amount of hydrographic, nutrient, and plankton data generated from various investigators on this cruise and use the report as a standard for the cruise participants. Data for temperature, salinity, oxygen, nitrate, nitrite, ammonium, phosphate, silicate, chlorophyll a, productivity indices, and carbon fixation rates are given.Prepared for the National Science Foundation under Grant OCE 77-26084, for the Office of Naval Research under Contract N00014-74-C-0262 ER 083-004 and for the NOAA Office of Sea Grant under Grants 04-7-158-44034 and 04-8-MO1-79 to the University of New Hampshire/University of Maine Cooperative Institutional Sea Grant Proqram

Hydrographic and nutrient data from R/V Atlantis II cruise 108, leg 3 : March to April 1981 : off the coast of Peru

In March and April of 1981 a major cruise was undertaken on the R/V Atlantis II off the Peruvian coast near 15°S in order to investigate the sea-air exchange of selected heavy metals and natural and anthropogenic organic compounds. The purpose of this report is to collate the hydrographic, nutrient, and plankton data generated from various investigators on this cruise end to provide a standard of reference for the cruise participants. Data for temperature, salinity, oxygen, nitrate, nitrite, axnmonium, phosphate, silicate, chlorophyll a, particulate organic carbon, and particulate organic nitrogen are given. In addition, air and sea temperatures, and wind speed and direction data, collected using the SAIL system, are included.Prepared for the National Science Foundation under Grants OCE 77-12914, OCE 80-17877 and OCE 81-11947

Organic biomarker compound concentrations in sediments from DSDP Hole 96-619

A study of organic biomarker compounds which could serve as tracers of terrigenous and marine sedimentary organic matter sources was performed on samples from a 208.7 m hydraulic piston core hole (DSDP Hole 619) from the hemipelagic Pigmy Basin in the northern Gulf of Mexico. Organic carbon-normalized concentrations of total long chain (C37-C39) alkenones and some individual C27-C29 desmethyl sterols were determined to be useful proportional indicators (tracers) of preserved marine and terrigenous organic carbon, respectively. The alkenones, whose only known source is marine phytoplankton of the class Prymnesiophyceae, generally occurred in higher concentrations in interglacial isotope stages 1 and 5a-b than in the intervening glacial stages. Sterols (C27-C29), apparently of a dominantly terrigenous origin, occurred in lower concentrations during interglacial stages than in glacial stages. Tracers of both terrigenous and marine organic matter appear to be affected by the differential diagenetic alteration of the biomarker/Corg ratios, as indicated by a simple, first-order kinetic model. The lack of any desmethylor 4a-methylsterol which is linearly related to the proportion of marine sedimentary organic matter (as scaled by d13Corg) indicates that either (1) sedimentary diagenesis has obscured the biomarker/Corg vs. d13Corg record, or (2) phytoplanktonic assemblage changes caused variations in the biomarker/Corg ratio of the primary input. Preferential preservation of terrigenous sterols may result in a biased sedimentary record of sterol input which could be misinterpreted as indicating solely terrigenous sterol sources. A simple model which characterizes the effects of sedimentary diagenesis on the relationship between Corg-normalized biomarker ratios and d13Corg demonstrates the potential problems of long-term, differential-diagenetic skewing on those tracer records