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<!--Modified on: 8/5/2014 2:21:49 PM-->
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  <xsd:element name="CashAndCashEquivalentsAndAvailableForSaleSecuritiesGrossUnrealizedLosses" id="snta_CashAndCashEquivalentsAndAvailableForSaleSecuritiesGrossUnrealizedLosses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="CommonStockAggregateOfferingPrice" id="snta_CommonStockAggregateOfferingPrice" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="PercentageOfGrossProceedsPayableAsCommission" id="snta_PercentageOfGrossProceedsPayableAsCommission" type="num:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardIncreaseInNumberOfSharesReservedForIssuance" id="snta_ShareBasedCompensationArrangementByShareBasedPaymentAwardIncreaseInNumberOfSharesReservedForIssuance" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOnOutstandingCommonStockForComputationOfAnnualIncreaseInNumberOfSharesReservedForIssuance" id="snta_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOnOutstandingCommonStockForComputationOfAnnualIncreaseInNumberOfSharesReservedForIssuance" type="num:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceAbstract" id="snta_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualLifeAbstract" id="snta_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualLifeAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingAggregateIntrinsicValueAbstract" id="snta_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingAggregateIntrinsicValueAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DebtInstrumentNumberOfEqualMonthlyPaymentsOfPrincipalPlusAccruedInterest" id="snta_DebtInstrumentNumberOfEqualMonthlyPaymentsOfPrincipalPlusAccruedInterest" type="xbrli:integerItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DebtInstrumentNumberOfEqualMonthlyPaymentsOfPrincipalPlusAccruedInterestForAdditionalBorrowingsAvailable" id="snta_DebtInstrumentNumberOfEqualMonthlyPaymentsOfPrincipalPlusAccruedInterestForAdditionalBorrowingsAvailable" type="xbrli:integerItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DebtInstrumentExitFeePayableAtEndOfTerm" id="snta_DebtInstrumentExitFeePayableAtEndOfTerm" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="DebtInstrumentCovenantEquipmentFinancingAllowedWithoutAnyRestriction" id="snta_DebtInstrumentCovenantEquipmentFinancingAllowedWithoutAnyRestriction" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="DebtInstrumentCovenantDebtAssumptionFromAcquisitionsRequiringPriorWrittenConsent" id="snta_DebtInstrumentCovenantDebtAssumptionFromAcquisitionsRequiringPriorWrittenConsent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="InterestExpenseRecognizedForDebtFinancingCosts" id="snta_InterestExpenseRecognizedForDebtFinancingCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="CommonStockVotingRightsNumber" id="snta_CommonStockVotingRightsNumber" type="xbrli:integerItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="RegisteredDirectOfferingMember" id="snta_RegisteredDirectOfferingMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AtTheMarketIssuanceSalesAgreementMember" id="snta_AtTheMarketIssuanceSalesAgreementMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DirectorsIncludingLargestShareholderMember" id="snta_DirectorsIncludingLargestShareholderMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DebtInstrumentAdditionalBorrowingsAvailable" id="snta_DebtInstrumentAdditionalBorrowingsAvailable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" id="snta_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" id="snta_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="EmployeeAndDirectorsStockOptionsMember" id="snta_EmployeeAndDirectorsStockOptionsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="CodevelopmentAndLicenseAgreementsDisclosureAbstract" id="snta_CodevelopmentAndLicenseAgreementsDisclosureAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FullPaymentOfOriginalLoan" id="snta_FullPaymentOfOriginalLoan" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
</xsd:schema>





