2 -Pyrimidinones tetrahydro- from

Propylene Urea Resins. In similat fashion to ethyleneurea, dimethyl-olpropyleneurea [3270-74-4] [l,3-bis(hydroxymethyl)tetrahydro-2-(m)-pyrimidinone] is the basis of propyleneurea—formaldehyde resin [65405-39-2], Its preparation is from urea, 1,3-diaminoptopane [109-76-2] and formaldehyde. 

During initiation with metal ions, a solvent can play the role of a donor ligand to this metal ion and thus enforce its activity. An example from Smij chemistry is as follows In mixtures of HMPA and l,3-dimethyl-3,4,5,6-tetrahydro-2(l//)pyrimidinone with AN (but not with THF), the rate of reductive cyclization of o-allyloxyiodobenzene with Sml2 sharply increases (Hasegawa and Curran 1993). 

Oxindoles are prepared using a solid-phase Pummerer reaction. Thus, the immobilized amide 182 undergoes the Pummerer rearrangement on treatment with TFAA and boron trifluoride diethyl etherate (BF3 Et20) (Equation 118). Cleavage of the oxindole from the linker is achieved using samarium iodide and 1,3-dimethyl-3,4,5,6-tetrahydro-2(lH)-pyrimidinone (DMPU) <2003CC2380>. 

Hexamethylphosphoric triamide is distilled from calcium hydride under reduced pressure of nitrogen. In place of hexamethylphosphoric triamide, 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)pyrimidinone (DMPU). which is dried and purified similarly,7 can be used. 

A 1,4-dipolar cycloaddition between tetrahydropyrido[l,2-a]pyrimidi-none 114 (R = Me) and 4-methyl-l, 2,4-triazoline-3,5-dione 666gave stable adduct 667 in acetonitrile or in acetic acid at room temperature for 1 hour (Scheme 44) (85CB4567). When ethyl cyanoformate was used as dienophile in boiling toluene for 20 hours, ethyl 3-methyl-4-oxo-6,7,8,9-tetrahydro-4//-pyrido[ 1,2-a]pyrimidine-2-carboxylate 669 was obtained (86CB1445). Pyrido[l,2-a]pyrimidine-2-carboxylate 669 was formed from the initial adduct 668 by elimination of phenyl isocyanate. Reaction of tetrahydropyr-ido[l,2-a]pyrimidinone 114 (R = Me) with l-(diethylamino)-l-propyne in... 

Heating a well-mixed mixture of l-(2-hydroxyethyl)-2-ethoxycarbo-nyl-6,7-dimethoxy-l,2,3,4-tetrahydroisoquinoline and solid NaOMe at 130 °C for 45 min followed by extraction of the reaction mixture with EtOAc provided 9,10-dimethoxy-1,6,7,11 b-tetrahydro-2H,4H-[l, 3]oxa-zino[4,3- ]isoquinolin-4-one in 52% yield (09T8021). 1,3,4,6,7,11b-Hexahydro-2H-pyrimido[6,l-fl]isoquinolin-4-one 53 was obtained from pyrimidinone 91 by a Pictet-Spengler reaction in CH2C12 in the action of TFA at ambient temperature (09OL1559). 

Let us turn now to the other coupling partner, aldehyde 58 it was synthesised by the pathway shown in Scheme 17.18. The first step was a Sharpless catalytic asymmetric epoxidation on ( )-crotyl alcohol with the oxidant derived from (—)-diethyl tartrate. An in situ derivatisation with r-butyldiphenylsilylchloride was then performed. The desired epoxide 59 was readily isolated in 76% overall yield after chromatography. Treatment of 59 with 2-lithio-l,3-dithiane in THF and 1,3-dimethyl-3,4,5,6-tetrahydro-2(l/7)-pyrimidinone (DMPU also known as N,N-... 

Because of the product s volatility, a hot water bath should not be used during solvent evaporation. GC and GC/MS analysis of an aliquot indicate that the product ranges in purity from 75-95% with unreacted 1-iodoheptane also present. The addition of 0.5 equiv of hexamethylphosphoramide (HMPA) prior to addition of the iodoheptane was found to improve the yield of this alkylation. The addition of 0.5 to 2.0 equiv of 1,3-dimethyl-3,4,5,6-tetrahydro-2(1 H)-pyrimidinone (DMPU) did not improve the yield. The checkers found the following GC conditions useful for monitoring the alkylation reaction initial column temperature, 40°C heating increment, fO°C/min iodoheptane R = 3.3 min, product R = 5.7 min. Column specifications were as follows SPB-f (stationary phase), fused silica gel capillary column, 30 m x 0.32 mm ID, 0.25-p.m film thickness. 

Weidner ef alP described a one-pot Smiles rearrangement method for the synthesis of various aminoquinolines from the corresponding hydroxyquinolines and showed that the tendency for the conversion depends on the electron-deficient nature of the quinolines. In a specific example, the reaction of 15 with (i) 2-bromo-2-methylpropionamide, 3 equiv. each of NaH and cesium carbonate in dioxane at reflux for 16 h and (ii) N-methylpyrrolidinone (NMP), l,3-dimethyl-3,4,5,6-tetrahydro-2(l//)-pyrimidinone (DMPU) (10 1 ratio) and 1 equiv. of NaH at 150 C for 72 h afforded the amine 16. 

Bonacorso HG, Costa MB, Lopes IS, Oliveira MR, Drekener RL, Martins MAP, Zanatta N, Flores AFC (2005) Synthesis of tetrahydro-2(lH)quinazolinones, cyclopenta[d]-2(lH) pyrimidinones and their thioxoanalogs from 2-trifluoroacetyl-l-methoxycycloalkenes. Synth Commun 35 3055-3064... 

Tetrahydro-2H-6H-pyrimido[2,l-b]-l,3-oxazine-2,4-diones from tetr ahy dro-1 -malonyl-2 (IH) -pyrimidinones... 

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