First conversion

The different internal and external file formats make it necessary to have programs which convert one format into another. One of the first conversion programs for chemical structure information was Babel (around 1992). It supports almost 50 data formats for input and output of chemical structure information [61]. CLIFF is another file format converter based on the CACTVS technology and which supports nearly the same number of file formats [29]. In contrast to Babel, the program is more comprehensive it is able to convert chemical reaction information, and can calculate missing atom coordinates [29]. 

The first conversion of protoberberines to phthalideisoquinoline alkaloids was achieved by Moniot and Shamma (88,89). 8-Methoxyberberinephenol-betaine (131), derived from berberine (15) (Section III,B,2), is an attractive compound having a carboxyl group masked as an imino ether in ring B. The masking was uncovered by hydration with water-saturated ether to furnish dehydronorhydrastine methyl ester (367) (Scheme 65). On N-methylation (68%) and subsequent sodium borohydride reduction (90%), 367 provided (+ )-/ -hydrastine (368) and ( )-a-hydrastine (369) in a 2 1 ratio. Compound 367 was converted to dehydrohydrastine (370), which also afforded 368 and 369 by catalytic hydrogenation. 

If we chose our first conversion increment as A/ = fx — f0 = 0.05, equation M indicates that... 

The importance of lattice coupling in direct molecular dissociation is at present poorly understood. However, there are at least two ways in which inclusion of the lattice can affect direct dissociative adsorption. First, conversion of Et to Eq competes with translational activation in dissociation. Second, thermal distortion of lattice atoms from their equilibrium positions may affect the PES, e.g., the barriers to dissociation V ( ). These two effects can be most simply thought of as a phonon induced modulation of the barrier along the translational coordinate and in amplitude, respectively. 

A device to multiply ion current in an electron beam (by first conversion to electrons). These electrons are then accelerated to another electrode, which in turn emits further secondary electrons so that the process can be repeated.4... 

Diones are normally synthesized from /3-hydroxy acids in two steps first, conversion into carbamates by reaction with sodium cyanate, and then cyclization with thionyl chloride (Scheme 103) (54JCS839). Alternative preparations utilize oxetanes, which may be combined either with isocyanates in the presence of boron trifluoride (68JAP6808278) or with S-alkylthioureas (Scheme 104) (69ZOR1844). In the last example the initial products are imines (224) which may readily be hydrolyzed to the required diones. Similar methods can be applied to the synthesis of tetrahydro-l,3-thiazine-2,4-diones, and, for instance, the 4-oxo-2-thioxo derivative (225) is obtained from /3-propiolactone and dithiocarbamic acid (Scheme 105) (48JA1001). 

It can be seen that the first conversion is relatively thermodynamically feasible. Thus, from the discussion above, the Fe ion in a selective oxidation catalyst should be near the fully oxidized state such that it can undergo the necessary reduction-oxidation cycle easily. It is significant to note that there is a substantial difference in the thermodynamic driving force (or resistance) between the first and the second reduction. This could be important in controlling the amount and the reactivity of the lattice oxygen in oxidation reactions. 

The first conversion is the a halogenation of an aldehyde. As described in Section 18.2, this particular conversion has been achieved in 80% yield simply by treatment with bromine in chloroform. 

Reformer operation and changes in operating rate should always be carried out in a way that ensures sufficient steam is over the catalyst. Thus, if the feed rate is to be increased, the steam rate should be increased first. Conversely, if the feed rate is to be decreased, the natural gas rate should be decreased first. 

Aldehydes and ketones can be regenerated from their tosylhydrazones by treatment with N-bromosuccinimide/CH3OH/acetone [49] or with H202/K2C03 [50], The mechanism of the first conversion is given in Scheme VIII/15. 

First, conversion of the units for the overall equation is required. 

Schwanert318 in 1860 observed probably the first conversion of furan derivatives into those of pyrrole. This reaction has been fully described,1 and is best carried out nowadays in the gas phase. Thus, furan or one of its derivatives is heated with ammonia or a primary amine to 400-450°, in the presence of activated aluminum oxide or aluminum silicate. The yield varies between 30 and 50% in most cases.319"324... 

The first conversion, which is exothermic, is practically complete between 400 and 600 C. At these temperatures the second, which is endothermic and exentropic and hence favored by low pressures, is still limited by an equilibrium, as shown by Table 1.7, where the calculation was made for an initial stoichiometric mixture of steam and methane at atmospheric pressure. 

In the first conversion, we multiplied the coefficient by one of the tens and ended up with one fewer ten in the exponential portion of the number. The values of all these numbers are the same only their format is different. We may need to change to different formats when we add or subtract exponential numbers, or we can use a scientific calculator. 

We have previously mentioned in Section 4.2 the chemistry developed by Selhnann etal, by using tetradentate or pentadentate S4 ligands. The use of such a ligand in nitrosyl ruthenium chemistry allowed the first conversion of a nitrosyl complex into a ruthenium HNO complex (31) by addition of NaBILi to [Ru(NO)(py S4)]Br. The formation and decomposition of HNO complexes is often invoked in many processes such as combustion of ftiels, oxidation of N2, reduction of HNO2, and so on. ... 

Thionolactones A method for conversion of lactones into the corresponding thionolactones involves first conversion of the lactone into the N,N-dimethyl-iminolactonium tetrafluoroborate (4) by a method used by Deslongchamps et al. Treatment of the salt 4 with sodium hydrosulfide in acetone at -78° for about 1 hour and then with acetyl chloride and pyridine (to trap the dimethylamine) results in the thionolactone 5. The low yield of 5 when n = 4 results mainly from cleavage to AcO(CH2)4C(=S)N(CH3)2. 

First conversion of primary alcohol 3 to the ferf-butyldiphenylsilyl ether 15 occurs. In the field of silyl ethers the TPS group as well as the triisopropylsilyl (TIPS) group are the most stable protecting groups against a large variety of reaction conditions - consequently they are frequently used in organic synthesis (see Chapter 2). ... 

We recorded our first conversation in his home in Fort Lee, New Jersey, on March 17, 1999. It was a full-day recording, which was then augmented by a shorter session in Fort Lee in late 2000, and the text was finalized in the summer of 2001. 

The first methanol was vaporised and reacted to produce hydrocarbons in the first conversion reactor as anticipated. However, the hi(J> prepane production due to high initial catalyst activity was not simulated. The actual unit heat balance was therefore not as predicted with the result that the process fired heater duty was significantly higher than expected. The startup heater which was in service to provide additional methanol superheat upstream of the DME reactor during startup was not taken off-line towards the end of startup as predicted. 

Condensation catalyst [1, 933-934, after citation of ref. 5]. 4-Chlorobutyryl chloride (0.71 mole) when treated with potassium fluoride (2.74 moles) at 195— 200° in tetramethylene sulfone is converted in 70% yield into cyclopropanecarb-oxylic acid fluoride.53 Evidence is presented that the reaction proceeds in two steps, first conversion of the acyl chloride into the fluoride, and then cyclization catalyzed... 

We continue constructing the unit analysis setup by writing the skeleton ofa conversion factor the parentheses, the line dividing the numerator and the denominator, and the unit that we know we want to cancel. This step helps to organize our thoughts by showing us that our first conversion factor must have the nm unit on the bottom to cancel the nm unit associated with 365 nm. 

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