Arctic acid

Advantage has been taken of the aforementioned observations in the synthesis of a terthiophene natural product, arctic acid (147) [123]. Pd-catalyzed carbonylation of bromobisthiophene 25, obtained from the Kumada coupling of 2-thienylmagnesium bromide and 2,5-dibromothiophene, gave bithiophene ester 144, which was converted to iodide 145 by reaction with iodine and yellow mercuric oxide. Subsequent propynylation of 145 was then realized using the Sonogashira reaction with prop-l-yne to give bisthienyl alkyne 146, which was subsequently hydrolyzed to 5 -(l-propynyl)-2,2 -bithienyl-5-carboxylic acid (147), a natural product isolated from the root of Arctium lappa. 

Arctic Acid Acetic Anhydride J Pyridine Acetal dot Paraldehyde... 

N.A. Inulin, mucilage, tannins, resin, arctin, arctic acid, arctiol, dehydro fukinone.99 100 For rheumatism, gout, and lung disease. It is laxative, diuretic, and perspiration inducer. 

Ju tliin preparation cliler-arctic. acid is converted into potassium cyauac.ot.ato, which is (lien hydrolysed aud esteriliod ill one operation ... 

Properties Brown powder. Mp 195C. Insoluble in water soluble in alcohol, oils, chloroform, glacial arctic acid. 

Arctic Acid Soils Neutral Soils Subtropical Tropical... 

Root contains inulin (up to approx. 45%) polyacetylenes (0.001-0.002%, dry-weight basis) consisting mainly of 1,1 l-tridecadiene-3,5,7,9-tetrayne and 1,3,1 l-tridecatriene-5,7,9-triyne arctic acid and lappaphens a and b (acetylenic acids containing S) volatile acids (acetic, propionic, butyric, isovaleric, 3-hexenoic, 3-octenoic, costic, etc.) and nonhydroxy acids (lauric, myristic, stearic, palmitic, etc.) a... 

Nordhftuser Schwefelsaure, Nordhftuser Vitri-oloL Nordhausen acid (fuming sulfuric acid), nordisch, a. northern, northerly, Nordic, nordlich, a. northerly, northern, arctic. Nord-licht, n. aurora borealis, -meer, n. Arctic Ocean, -ost, m. northeast northeaster, -pol, m. north pole. -see,/. North Sea. Norgeraniumsaure,/. norgeranic acid. Norgesalpeter, m. Norway saltpeter (calcium nitrate). 

Thamnolia vermicularis is an arctic-alpine, fruticose, soil-dwelling lichen that enjoys a very wide distribution. The species consists of two chemical strains, one predominantly found in the Northern Hemisphere and the other in the Southern Hemisphere, with most populations from intermediate regions exhibiting intermediate chemical types. Sato (1965) showed that the southern strain accumulates thamnolic acid [403], whereas the northern strain is characterized by two compounds, squamatic acid [404] and baeomycic acid [405]. Populations from Greenland, Novaya Zemlya, and Svalbard exhibited only the northern profile. Two populations from South America exhibited only the southern type, while collections from New Zealand showed nearly pure southern type. 

Most plant species are able to absorb and assimilate nitrate, ammonium, urea, and amino acids as nitrogen sources, but the response to a particular form of nitrogen varies from species to species (114). For example, optimal growth of tomato roots occurs in soil with a ratio of nitrate to ammonium of 3 1 and is inhibited if the ammonium concentration is too high (115). By contrast, white spruce has a strong preference for ammonium (116), whereas some arctic sedges prefer amino acids (117). 

The various fields of chemistry play an important role in the discovery and exploitation of oil and gas reserves. Improved drilling and well completion fluids, cement slurries, hydraulic fracturing and acidizing fluids to improve well productivity, various chemical additives to be used in these fluids, and chemicals for enhanced oil recovery are essential to the improvement of production economics and to an increase in recoverable hydrocarbon reserves. Chemistry will become increasingly important in future hydrocarbon production with the decreased likelihood of major onshore discoveries, increased discovery and production costs associated with deep offshore wells and Arctic frontier provinces, and the decline in drilling since early 1982. 

Arctic char, Salvelinus alpinus Austria acidic lake 19.n nvv Oft ... 

We can see that the content of trace metals in water extraction is very low. This means that the direct involvement of these metals in biogeochemical cycles is very restricted. The significant increase of metal contents in acid-soluble form was shown only for Fe, Mn and, partly, for Zn. These data testify the importance of atmospheric deposition for the Arctic ecosystems as a source of nutrients. 

Karsten U, Franklin LA, Liming K, Wiencke C (1998) Natural ultraviolet radiation and photosyn-thetically active radiation induce formation of mycosporine-like amino acids in the marine macroalga Chondrus crispus (Rhodophyta). Planta 205 257-262 Karsten U, Bischof K, Hanelt D, Tug H, Wiencke C (1999) The effect of ultraviolet radiation on photosynthesis and ultraviolet-absorbing substances in the endemic Arctic macroalga Devaleraea ramentacea (Rhodophyta). Physiol Plant 105 58-66 Kessler A, Baldwin IT (2002) Plant responses to insect herbivory the emerging molecular analysis. Ann Rev Plant Biol 53 299-328... 

McKnight, D. M., and K. E. Bencala (1988), "Dial Variations in Iron Chemistry in an Acidic Stream in the Colorado Rocky Mountains", Arctic and Alpine Research 20, 492-500. 

The distribution of the total N in amino acids, amino sugars and ammonia in soils formed under widely differing climatic conditions was determined by Sowden et al. [4] The soil samples originated from the arctic, cool temperate, subtropical, and tropical regions of the earth s surface. All samples were analyzed by the same methods, which provided a degree of uniformity which had not been attained before and made it possible to gain new insights into the distribution of N in soils. Table 8.1... 

From the amino acid data in Table 8.2, protein N was calculated to make up 36, 40.46 and 45 % of the total N in the arctic, cool temperate, subtropical and tropical soils, respectively, averaging 42 %. Thus, about 58 % of the total N in soils was nonprotein. Amino sugars in the soils constituted between 4.5 and 7.4% of the total N, with soils under warmer climates containing more amino sugars than those under cooler dimates. 

Many of the PCBs found in the aquatic environment (e.g., in lakes and in the Arctic and Antarctic) have migrated via atmospheric dispersion of vapors [404-410]. Vaporization of PCBs from soil decreases as the amount of humic material in the solid phase increases due to mainly partitioning processes [381-390]. Griffin and Chian [363] note that vaporization of PCBs from suspensions of solids or humic acids is reduced by the presence of these materials. 

In putrebactin from Shewanella putrefaciens (201) cadaverine is replaced by pufrescine (49, R = H). For the cyclic trimer, see proferrioxamine X2 in Table 6. The arctic S. gelidimarina living in a habitat with extremely low iron supply produces a cell-associated hydroxamic acid siderophore with the mass 977 Da for of unknown structure (274). 

---