ORGLIST: Re: Everybody Digest, Vol 13, Issue 18

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From: Lakshmipathi Pandarinathan (plpathi$##$hotmail.com)
Date: Tue Oct 25 2005 - 15:14:52 EDT


2. Use of phosphorus pentachloride in acid chloride synthesis (cardman)
You could use excess of oxalyl chloride (5-10 eqs) and add catalytic amount
(a drop) of dimethylformamide. The reaction can be run in dichloromethane
and will be completed in less than an hour. Remove the solvent and excess
oxalyl chloride under vacuum or by simply putting a stream of nitrogen. The
crude residue obtained can be directly used for esterification.
Pathi

5. RE: MOM group stability (will jones)

Ester hydrolysis by a mild condition could be by using LiOH (1-2 eq) in
THF/MeOH/Water (8:2:1) and the reaction can be run at rt to 60 deg C
depending upon the substrate. Reaction will be completed by two- four hrs
time. I think this will not affect your MOM or Boc protecting groups on N.
Pathi

----- Original Message -----
From: <everybody-request$##$orglist.net>
To: <everybody$##$orglist.net>
Sent: Tuesday, October 25, 2005 12:03 PM
Subject: Everybody Digest, Vol 13, Issue 18


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> Today's Topics:
>
> 1. RE: alpha,alpha dibrom acetophenone (Ilya Avrutov)
> 2. Use of phosphorus pentachloride in acid chloride synthesis
> (cardman)
> 3. RE: epoxidation help (will jones)
> 4. 2-amino-3-nitro pyridine (Kishore Babu Ch)
> 5. RE: MOM group stability (will jones)
> 6. RE: Use of phosphorus pentachloride in acid chloride
> synthesis (will jones)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 24 Oct 2005 11:24:46 -0400
> From: "Ilya Avrutov" <IAvrutov$##$dalton.com>
> Subject: RE: ORGLIST: alpha,alpha dibrom acetophenone
> To: "Kishore Babu Ch" <kbchilukuri$##$yahoo.com>, <everybody$##$orglist.net>
> Message-ID:
> <3C4E01DBE4138446A742AC296B57F30D2EA139$##$dalton-es.dalton.dcl>
> Content-Type: text/plain; charset="US-ASCII"
>
> Dear Kishore,
>
> What condition did you try with Bromine. Try the reaction at boiling and
> take excess of bromine. I don't have any reference, just common sense.
>
> Best regards,
> Ilya
>
>
> ------------------------------------
> Dalton Pharma Services
> Ilya Avrutov
> Process Development Group Leader
> iavrutov$##$dalton.com
> 349 Wildcat Rd. Toronto ON M3J 2S3
> tel: 416-661-2102 (320)
> fax: 416-661-2108
> mobile: 416-726-2556
> ------------------------------------
>
> -----Original Message-----
> From: everybody-bounces$##$orglist.net
> [mailto:everybody-bounces$##$orglist.net] On Behalf Of Kishore Babu Ch
> Sent: Monday, October 24, 2005 8:34 AM
> To: everybody$##$orglist.net
> Subject: ORGLIST: alpha,alpha dibrom acetophenone
>
> Dear sir/madam,
>
> Please suggest the how to prepare the alpha,alpha dibrom acetophenone
> from acetophenone .I try with NBS and Bromine .It converted only phencyl
> bromide.Please suggest any reference.
>
> thanks,
> ch.kb
> Mail id: kbchilukuri$##$yahoo.com
>
>
>
>
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> ------------------------------
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> Message: 2
> Date: Mon, 24 Oct 2005 18:04:39 -0700 (PDT)
> From: cardman <cardman400$##$yahoo.com>
> Subject: ORGLIST: Use of phosphorus pentachloride in acid chloride
> synthesis
> To: everybody$##$orglist.net
> Message-ID: <20051025010439.63619.qmail$##$web80905.mail.scd.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
>
> Does anyone have any tips on the use of PCl5 ? I tried
> using a 1:1 molar ratio of pentachloride and
> 4-azidobenzoic acid in refluxing benzene and got a
> yield of only 50% of the acid chloride. Of course I
> thought about using a large excess of chloride to
> drive the rxn forward, but then how do I separate off
> the xs? I want to carry out an esterification, so I
> can't just use the reaction mixture as it is (or can
> I?).
>
> Actually, the same thing happened with oxalyl
> chloride: I recrystallized the residue, and a
> significant portion of the unreacted acid crystallized
> out first.
>
> I can't use thionyl chloride because my company has to
> first apply for a permit. Apparently thionyl chloride
> is on the DEA's list of restricted chemicals.
>
>
>
>
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> ------------------------------
>
> Message: 3
> Date: Mon, 24 Oct 2005 21:06:47 +0000
> From: "will jones" <willjones46$##$hotmail.com>
> Subject: RE: ORGLIST: epoxidation help
> To: sunil.silvary$##$gmail.com, everybody$##$orglist.net
> Message-ID: <BAY102-F29A999FB004A9CDE2966C7AE770$##$phx.gbl>
> Content-Type: text/plain; format=flowed
>
> So if your H2O2 is 9.8M, then in 1L of it, you have 9.8mol of H2O2.
> In 100mL you therefore have 0.98mol and if you want to know how much is in
> 115mL, then..
> 0.98x1.15=1.127mol. That's how they got it.
>
> Will
>
>
>>From: Sunil Silvary <sunil.silvary$##$gmail.com>
>>To: everybody$##$orglist.net
>>Subject: ORGLIST: epoxidation help
>>Date: Sun, 23 Oct 2005 21:34:35 -0400
>>
>>Hi,
>>I am doing an epoxidation reaction and following the procedure given in
>>org.syn vol IV in the procedure it is given that 1.2 moles of H2O2 is
>>115ml.
>>I do not understand how they got that value. The H202 that I bought from
>>aldrich has a density of 1.11 gm/ml and molarity of 9.8M. I tried
>>calculating as usual by using and molarity=moles/litre and d=m/v
>>relationship but i am not getting that value.
>> Is there is special way for converting moles to volume for H2O2 ? Please
>>help if you know the method, if possible in detail.
>> thanking you,
>>sunil
>
>
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>
> ------------------------------
>
> Message: 4
> Date: Tue, 25 Oct 2005 04:48:26 -0700 (PDT)
> From: Kishore Babu Ch <kbchilukuri$##$yahoo.com>
> Subject: ORGLIST: 2-amino-3-nitro pyridine
> To: everybody$##$orglist.net
> Message-ID: <20051025114827.90565.qmail$##$web51511.mail.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
>
> Dear sir,
>
> Please suggest the how to prepare the 2-amino-3-nitro
> pyridine.I try Nitration at 60 C . 3- nitro we getting
> only 10% yield ,remaining is 5 nitro .Please suggest
> any literature and any method.
>
> ch.k
> Mail id:kbchilukuri$##$yahoo.com
>
>
>
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>
> ------------------------------
>
> Message: 5
> Date: Mon, 24 Oct 2005 21:14:04 +0000
> From: "will jones" <willjones46$##$hotmail.com>
> Subject: RE: ORGLIST: MOM group stability
> To: raghumorthala$##$rediffmail.com, everybody$##$orglist.net
> Message-ID: <BAY102-F9F4705F18D2853A3EC0D0AE770$##$phx.gbl>
> Content-Type: text/plain; format=flowed
>
> Both groups you have mentioned are stable up to pH 12. You can therefore
> hydrolyse in the presence of NaOH provided that you dont heat too much and
> the pH isnt above 12. You can usually use a 1:1 dioxane:water/NaOH to
> effect
> ester hydrolysis.
>
> Will
>
>
>>From: "morthala raghavendar rao" <raghumorthala$##$rediffmail.com>
>>Reply-To: morthala raghavendar rao <raghumorthala$##$rediffmail.com>
>>To: everybody$##$orglist.net
>>Subject: ORGLIST: MOM group stability
>>Date: 23 Oct 2005 21:43:27 -0000
>>
>>
>>Hi there,
>>
>>I am doing one reaction wherein I need to hydrolyse ester group of N-MOM
>>and BOC protected amino acid using NaOH. Is any one know whether the MOM
>>group is stable with NaOH/ethanol reflux or not. If it is not stable could
>>you tell me which method is suitable for this hydrolysis without affecting
>>MOM group.
>>
>>Thanks
>>Raghavendar Rao
>>
>
>
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> ------------------------------
>
> Message: 6
> Date: Tue, 25 Oct 2005 14:24:52 +0000
> From: "will jones" <willjones46$##$hotmail.com>
> Subject: RE: ORGLIST: Use of phosphorus pentachloride in acid chloride
> synthesis
> To: cardman400$##$yahoo.com, everybody$##$orglist.net
> Message-ID: <BAY102-F312351D8900AFF1D8096CAE760$##$phx.gbl>
> Content-Type: text/plain; format=flowed
>
> If you are carrying out an esterification, then use coupling agents such
> as
> DCC. the reaction is best carried out in dcm if you can, although I use
> dcc
> in loads of solvents. the product, dcu is easily separated as it is
> insoluble in most solvents. You can carry out the coupling reaction with
> the
> carboxylic acid and alcohol in situ.
>
> This is much easier than using PCl5.
>
> Will
>
>
>>From: cardman <cardman400$##$yahoo.com>
>>To: everybody$##$orglist.net
>>Subject: ORGLIST: Use of phosphorus pentachloride in acid chloride
>>synthesis
>>Date: Mon, 24 Oct 2005 18:04:39 -0700 (PDT)
>>
>>Does anyone have any tips on the use of PCl5 ? I tried
>>using a 1:1 molar ratio of pentachloride and
>>4-azidobenzoic acid in refluxing benzene and got a
>>yield of only 50% of the acid chloride. Of course I
>>thought about using a large excess of chloride to
>>drive the rxn forward, but then how do I separate off
>>the xs? I want to carry out an esterification, so I
>>can't just use the reaction mixture as it is (or can
>>I?).
>>
>>Actually, the same thing happened with oxalyl
>>chloride: I recrystallized the residue, and a
>>significant portion of the unreacted acid crystallized
>>out first.
>>
>>I can't use thionyl chloride because my company has to
>>first apply for a permit. Apparently thionyl chloride
>>is on the DEA's list of restricted chemicals.
>>
>>
>>
>>
>>__________________________________
>>Yahoo! FareChase: Search multiple travel sites in one click.
>>http://farechase.yahoo.com
>>_______________________________________________
>>ORGLIST - Organic Chemistry Mailing List
>>Website / Archive / FAQ: http://www.orglist.net
>>To post a message (TO EVERYBODY) send to everybody$##$orglist.net
>>To unsubscribe, send to everybody-request$##$orglist.net the message:
>>unsubscribe your_orglist_password your_address
>
>
>
>
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>
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> End of Everybody Digest, Vol 13, Issue 18
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