Bruno Forte, “María, mujer icono del misterio”

pi*oportion8 of sodium ziltrito and molecular proportion Of Qoetle oold at -8 to -3^0» and estimated to oontoin

1 *404 g. (92.40 of the theoretloel quantity) of ohitose* was evaporated under diminished proeeure at 23-25^0. to a moderately mobile oyrup# The product woo dehydrated by repeated extraction with pure ooetono end the omorphouo

residue of prootieelly dry ohitoee freed from trooee of acetone by placing it under high vacuum at 80^0, for 10 minu: To what oxtoat the ehitooo hod imdergoao decompoeltlon during these proceeeee wee determined by dieaolvlng in water* mskiuf up to 20 ml, in e graduated flask and carrying out the chltof oatlmatlon method on the solution, 91,70 of the original quantity of chltose was found to bo preeent or 85,6# of the theoretical amount obtainable from the glucoeam ine hydro­ chloride deemineted.

Condensation of ohItose with methyl eloobol.

Having obtained s ouitable method for the proparetion of dry ohitoae in good yield and containing praotioelly ao undeemlnated gluooeemiae* further luveetlgetlons were mode into its ooudenoetloa with methyl alcohol,

Methyl ehitoBlde*

The rotation of an almost neutral oolution of approxi­ mately 50 ehitoee in dry methyl alcohol at room temporoture woe observed over a period of 5 days but apart from a very email initial Inorooee the rotatory power remained imaltored. At the Game time the reducing i)o%&or of the solution was

tested by adding 0,5 ml, to 8 ml, of cold Fehling's solution end observing the deposit of cuprous oxide which* after a few hours* lied completely settled at the hot tom of the teat tui)e, A Gonelderable deposit wee obtained in a test on the freshly prepared solution but the omoimt was markedly reduced after the solution had been left at room temperature for 24 hours# Ho further decreaae In reducing power was noted aftei the solution had been left at room temperature for a further period of 4 days, From this observed decreaae In reducing power of the aolution it wan conE$idered that condensation of chit080 and methyl alcohol had occurred with the formation of either methyl chitoeide or chltose dimethylaoetal, A test portion of the solution* made faintly alkaline by the addltlo: of a very email quantity of anhydrous oodium carbonate which*

(( it W88 hoped* %Youl(% roduoe hydrolysis to a minimum* vmo evapo%*eted at low temperature to o white brittle amorphouQ solid of constant weight, The methoxyl eontont of this material (6.8#) confirmed the ouepicio)i that e oertg degree of ooadenaotioa had token plaoe. Attempts at séparai loa of the methylated product from unchanged ohit use by

extraction with verioue solvents were imeuoooaeful. The

foot that the materiel eontained ao ethyl acetate soluble

portion 8hov;ed that no chitoae (iimothylaeetol was %)roam%t. It was realised that the proeenoe of email amoimte of oodium acetate and sodium oarhonate in the product ioolatod in the above experiment might be reeponeible for a eonaider'* able proportion of the estimated methoxyl oontent by virtue of the foot that they probably retain a quantity of methyl alcohol of cryetaliieation. The effect of the prceenoe of theee aalta wee examined by adding an excess of anhydrous sodium carbonate to a 1# solution of acetic acid in dry methyl aloohol end evaporating the resulting alkaline

solution to a dry solid maae under the coiditiono described for the isolation of the chiatc^ condoaeatlon product#

Botlmation of the methoxyl content of the salt mixture (4#6# and calculation of the quantities prcaent in the methyl

chltoolde preparation ahowed that only a email fraction of the methyl iodide liberated in the methokyl estimation of

'met%)yl chitoelde' could be derived from this eource#

The addition of a email amouht of glacial acetic acid to the remainder of the chltoae in methyl alcohol giving a

(<

solution ôiGtinotly eold to litmus o W eoatalmlag opproxlmeti 0.025^ aoetlo acid did not affect the rotatory poi?er over a period of three deye and there wee no marked decreeee in the

rodwing poxver of the solution* The product hov/evoz* leoleted from a toot portion of the eolutloa no ixi the previous case wae found to hove increeced in methoxyl

ooatont to

10

2

eqnlllhrinm the rovcrolhle react! m i:-

Ohitoee Methyl alcohol Methyl ohitoslde ^ Prom the foot that condensation takes place even In

neutral oolntlon with the production of what la prohohly methyl chltoelde it was conaidered likely that the reverse

reaction,namely the hydrolysis of methyl chltooide to chit oej end methyl eleoliol, would also he readily effected in slight] acid or n A w a l solution. This was borne out by tho fact the whereas the product, isolated from the chltoce solution in methyl alcohol containing acetic acid by making alkaline with a l i t t l e anhydrous sodium carbonate end evaporating to Q dry eolid, had a methoxyl content of 10$ 5^» the eeme

solution on evaporation wit?iOut noturaliaatlon with sodium carbonate gave a product having a methoxyl content of only

62)