tert-Butyl 5-(4-methoxy­phen­yl)-1-methyl-2-oxopyrrolidin-3-yl carbonate

In the title compound, C17H23NO5, the pyrrolidinone ring is in an envelope conformation. The tert-butyl carbonate and 4-methoxy­phenyl groups are arranged on the same side of the pyrrolidinone ring. The meth­oxy group is coplanar with the attached benzene ring. The mol­ecules are linked into chains along the b axis via C—H⋯O hydrogen bonds

4-Hydr­oxy-5-(4-methoxy­phen­yl)pyrrolidin-2-one

In the title compound, C11H13NO3, the pyrrolidin-2-one ring is in an envelope conformation with the hydroxyl and 4-methoxy­phenyl substituents mutually cis. The methoxy group is slighty twisted away from the mean plane of the attached benzene ring. The mol­ecules are arranged into screw chains along the c axis. These chains are inter­connected via inter­molecular O—H⋯O and N—H⋯O hydrogen bonds into sheets parallel to the ac plane. The crystal structure is further stabilized by weak inter­molecular C—H⋯O and C—H⋯π inter­actions

Response of carbon dioxide emissions to sheep grazing and N application in an alpine grassland – Part 2: Effect of N application

Widespread nitrogen (N) enrichment resulting from anthropogenic activities has led to great changes in carbon exchange between the terrestrial biosphere and the atmosphere. Grassland is one of the most sensitive ecosystems to N deposition. However, the effect of N deposition on ecosystem respiration (<i>R</i>_e) in grasslands has been conducted mainly in temperate grasslands, which are limited largely by water availability, with few studies focused on alpine grasslands that are primarily constrained by low temperatures. Failure to assess the magnitude of the response in <i>R</i>_e outside the growing season (NGS) in previous studies also limits our understanding of carbon exchange under N deposition conditions. To address these knowledge gaps we used a combination of static closed chambers and gas chromatography in an alpine grassland from 2010 to 2011 to test the effects of N application on ecosystem respiration (<i>R</i>_e) both inside and outside the growing season. There was no significant change in CO₂ emissions under N application. <i>R</i>_e outside the growing season was at least equivalent to 9.4% of the CO₂ fluxes during the growing season (GS). Annual <i>R</i>_e was calculated to be 279.0–403.9 g CO₂ m⁻² yr⁻¹ in Bayinbuluk alpine grasslands. In addition, our results indicate that soil temperature was the dominant abiotic factor regulating variation in <i>R</i>_e in the cold and arid environment. Our results suggest that short-term N additions exert no significant effect on CO₂ emissions in alpine grassland

Lower land-use emissions responsible for increased net land carbon sink during the slow warming period

The terrestrial carbon sink accelerated during 1998–2012, concurrently with the slow warming period, but the mechanisms behind this acceleration are unclear. Here we analyse recent changes in the net land carbon sink (NLS) and its driving factors, using atmospheric inversions and terrestrial carbon models. We show that the linear trend of NLS during 1998–2012 is about 0.17 ± 0.05 Pg C yr−2 , which is three times larger than during 1980–1998 (0.05 ± 0.05 Pg C yr−2). According to terrestrial carbon model simulations, the intensification of the NLS cannot be explained by CO2 fertilization or climate change alone. We therefore use a bookkeeping model to explore the contribution of changes in land-use emissions and find that decreasing land-use emissions are the dominant cause of the intensification of the NLS during the slow warming period. This reduction of land-use emissions is due to both decreased tropical forest area loss and increased afforestation in northern temperate regions. The estimate based on atmospheric inversions shows consistently reduced land-use emissions, whereas another bookkeeping model did not reproduce such changes, probably owing to missing the signal of reduced tropical deforestation. These results highlight the importance of better constraining emissions from land-use change to understand recent trends in land carbon sinks

Synthesis of 2,3-Dioxo-5-(substituted)arylpyrroles and Their 2-Oxo-5-aryl-3-hydrazone Pyrrolidine Derivatives

Some novel2,3-dioxo-5-(substituted)arylpyrroles have been synthesized. Among these, pyrrolidine compound 1b was converted to 2,3-dioxo-5-aryl pyrrolidine 2b. Finally a set of hydrazone derivatives was obtained from the reaction of 2b with various hydrazine salts. The structures of all the new synthesized compounds were confirmed by elemental analyses, IR and 1H-NMR spectra